Exploring the implementation of role extension for Namibian radiographers: Perspectives on intravenous injection of contrast media.

INTRODUCTION: Role extension to include intravenous (IV) injection of contrast media has been formally embraced by radiographers and their regulatory bodies in developed countries. The revised scope of practice, in our Namibian context, has formalised IV injection as an extended role for radiographers. This study aimed to explore the perspectives of radiographers regarding this new role of IV injection of contrast media. METHODS: A qualitative design with a descriptive phenomenological approach was employed to collect data from 15 radiographers working in both public and private radiology facilities. Participants were purposively selected to participate in focus group discussions and individual interviews. An interview guide was used to facilitate the discussions and interviews, and a voice recorder was used for recording. Data were transcribed verbatim and analysed using Tesch's 8-step method. RESULTS: From the 15 participants, three themes were developed: enhanced service delivery with two subthemes (improved departmental workflow and patient care), training needs with two subthemes (inadequate contrast media reaction training and standardised training requirement), and medical-legal issues with two subthemes (regulatory blurriness and role conflict distress). CONCLUSION: The participants expressed mixed perceptions towards the IV injection role of radiographers, emphasising the benefits for the department and patients while raising concerns regarding standardisation of training and associated medico-legal issues. Furthermore, a large-scale evaluation is necessary to uncover the challenges and barriers to the successful adoption of this new role. IMPLICATIONS FOR PRACTICE: The role extension for radiographers to include IV injections is a long-awaited development, but it should be accompanied by the necessary training and guidelines to fully realise its benefits.

Higher sustained virological response rates at 12 weeks in HIV-HCV co-infection; a tertiary centre experience.

OBJECTIVES: The advent of direct-acting antivirals (DAAs) has revealed high rates of sustained virological response at 12 weeks (SVR 12) in Hepatitis C (HCV) treatment. Since the introduction of DAAs, in our centre, 42% of patients treated for HCV are HIV co-infected. Our study aimed to identify the SVR 12 rates between this group and HCV mono-infected patients. METHODS: Retrospective data analysis of HCV mono-infection and HIV-HCV co-infection patients between 1st July 2015 and 30th November 2018, who had a SVR at 12 weeks post treatment. Co-infected patients were only referred for HCV treatment if they had well controlled HIV. Patients treated with Pegylated Interferon and Ribavirin were excluded. RESULTS: During this period, 724 patients were treated for HCV and had data on SVR 12. Of those, 303 (41.8%) were co-infected with HIV. The SVR 12 was achieved in 386 (91.6%) of the HIV negative patients and 288 (95%) of the HIV positive patients (χ²= 3.10 p = 0.078). Cirrhotic patients had poorer SVR 12 in both groups (90% in co-infection and 88.4% in HCV mono-infection). CONCLUSIONS: Our results demonstrate a higher SVR 12 in co-infected patients compared to patients with HCV mono-infection. We hypothesise that adherence to HIV treatment could increase compliance and success of HCV treatment.

Hoarse voice in adults: an evidence-based approach to the 12 minute consultation.

BACKGROUND: The hoarse voice is a common presentation in the adult ENT clinic. It is estimated that otolaryngology/voice clinics receive over 50 000 patients with dysphonia each year. Good vocal function is estimated to be required for around 1/3 of the labour force to fulfil their job requirements. The assessment and management of the patient with a hoarse voice is potentially a complex and protracted process as the aetiology is often multi-factorial. This article provides a guide for the clinician in the general ENT clinic to make a concise, thorough assessment of the hoarse patient and engage in an evidence based approach to investigation and management. METHOD: Literature search performed on 4 October 2008 using EMBASE, MEDLINE, Cochrane databases using subject headings hoarse voice or dysphonia in combination with diagnosis, management, investigation, treatment, intervention and surgery. RESULTS: General vocal hygiene is beneficial for non organic dysphonia but the evidence base for individual components is poor. There is a good evidence base for the use of voice therapy as first line treatment of organic dysphonia such as vocal fold nodules and polyps. There is little evidence for surgical intervention as first line therapy for most common benign vocal fold lesions. Surgery is, however, the treatment of choice for hoarseness due to papillomatosis. Both CO(2) laser and microdissection are equally acceptable modalities for surgical resection of common benign vocal fold lesions. Laryngopharyngeal reflux is commonly cited as a cause of hoarseness but the evidence base for treatment with gastric acid suppression is poor. Despite the widespread use of proton pump inhibitors for treating laryngopharyngeal reflux, there is high quality evidence to suggest that they are no more effective than placebo. CONCLUSION: A concise and thorough approach to assessment in the general ENT clinic will provide the diagnosis and facilitate the management of the hoarse voice in the majority of cases. Voice therapy is an important tool that should be utilised in the general ENT clinic and should not be restricted to the specialist voice clinic. If there is no improvement after initial measures, the larynx appears normal and/or the patient has failed initial speech & language therapy, referral to a specialist voice clinic may be helpful. More research is still required particularly with regard to laryngopharyngeal reflux which is often cited as an important cause of hoarseness but is still poorly understood.

Effects of dissolved polymer on the transport of colloidal particles through a microcapillary.

The effect of water-soluble polymer on the transport of latex particles through a microcapillary was investigated. Capillary hydrodynamic fractionation (CHDF) experiments were performed using polystyrene (PS) particles and poly(ethylene oxide) (PEO) solutions as the eluant. Generally, the average particle velocities were greater than those corresponding to a polymer-free eluant. A decrease in the sample axial dispersion was also observed using the PEO solutions. In addition, increasing the polymer molecular weight resulted in lower particle residence times in the capillary tube. The enhanced particle transport arises primarily from an increase in the particle diameter resulting from the adsorption of PEO onto the PS surfaces, and, more importantly, from the migration of particles toward the capillary axis due to the normal stress of the PEO solution.

Expression of cardiomyocytic markers on adipose tissue-derived cells in a murine model of acute myocardial injury.

Animal and early clinical studies have provided evidence suggesting that intracoronary administration of autologous bone marrow-derived cells results in improved outcome following myocardial infarction. Animal studies with cultured marrow stromal cells (MSC) have provided similar data. Cells with properties that are similar to MSC have been identified in adipose tissue. Other groups have demonstrated in vivo differentiation of adipose tissue-derived cells (ADC) into cells exhibiting biochemical and functional markers of cardiac myocytes, including spontaneous beating. Based on these observations, the objective of the present study was to determine whether ADC might undergo similar differentiation in vivo in the context of myocardial injury.ADC were isolated from subcutaneous adipose tissue of Rosa26 mice (which express the beta-galactosidase transgene in almost every tissue) and injected into the intraventricular chamber of B6129S recipient mice immediately following induction of myocardial cryoinjury. Groups of recipients were euthanized at 24 hours, 7 and 14 days post surgery and examined for the presence of donor-derived cells within the heart.Beta-gal positive cells were identified in the infarcts of ADC-treated animals. No staining was observed in uninjured myocardium or in infarcts of control animals. Immunohistochemical analysis revealed co-expression of beta-gal with Myosin Heavy Chain, Nkx2.5 and with Troponin I. Co-expression of beta-galactosidase with Connexin 43, CD31, von Willebrand factor, MyoD or CD45 was not detected.Thus, these data indicate that adipose tissue contains a population of cells that has the ability to engraft injured myocardium and that this engraftment is associated with expression of cardiomyocytic markers by donor-derived cells.

The development of a palliative care program for managed care patients: a case example.

Palliative care is emerging as an important new field. Although programs are developing in hospital environments, little is known about development of programs in outpatient practices or those serving large managed care populations. This article provides a framework for the development of a comprehensive palliative care program in a large multispecialty group practice that serves managed care patients. The article addresses guiding principles, the need for obtaining baseline data, how the clinical consultation service was established, development of outcomes measures, and information on current program status. Five themes emerged as key to successful program development, most importantly the close collaboration between administrative and clinical staff in all aspects of program development.

Health-related quality of life in narcolepsy.

Narcolepsy is a chronic sleep disorder characterised by symptoms of excessive daytime sleepiness and cataplexy. The aim of this study was to describe the health-related quality of life of people with narcolepsy residing in the UK. The study comprised a postal survey of 500 members of the UK narcolepsy patient association, which included amongst other questions the UK Short Form 36 (SF-36), the Beck Depression Inventory (BDI), and the Ullanlinna Narcolepsy Scale (UNS). A total of 305 questionnaires were included in the final analysis. The results showed that the subjects had significantly lower median scores on all eight domains of the SF-36 than normative data, and scored particularly poorly for the domains of role physical, energy/vitality, and social functioning. The BDI indicated that 56.9% of subjects had some degree of depression. In addition, many individuals described limitations on their education, home, work and social life caused by their symptoms. There was little difference between the groups receiving different types of medication. This study is the largest of its type in the UK, although the limitations of using a sample from a patient association have been recognised. The results are consistent with studies of narcolepsy in other countries in demonstrating the extensive impact of this disorder on health-related quality of life.

Serum osteocalcin has limited usefulness as a diagnostic marker for rickets.

UNLABELLED: Serum alkaline phosphatase (AP), the bone fraction of which is secreted by osteoblasts, is elevated in rickets. Both normal and elevated levels of serum osteocalcin (OC), a bone-specific marker secreted by osteoblasts, have been reported in rickets. Expression of the OC gene is enhanced by 1,25-dihydroxyvitamin D (1,25(OH)2D) in experimental models. This study assessed serum OC levels in 14 controls and 41 patients with active rickets divided into a phosphopenic (n = 20) and a calciopenic (n = 21) group. Phosphopenic subjects were older (9.5 versus 5.7 years, P = 0.03) with higher median serum calcium level (2.35 versus 2.16 mmol/l, P = 0.0002) and serum 25-hydroxyvitamin D level (15.4 versus 10.4 ng/l, P = 0.003); and lower serum phosphate (0.80 versus 1.51 mmol/l, P = 0.0001), serum 1,25(OH)2D (43.0 versus 95.6 pg/ml, P = 0.0001) and intact serum parathyroid hormone level (45.0 versus 141.5 ng/l, P = 0.01) than calciopenic subjects. There were no differences in median serum AP (774 versus 1430 IU/l, P = 0.17) and OC (14.5 versus 13.4 ng/ml, P = 0.6) between the two groups. The mean OC value for the 41 rickets subjects was 15.1 +/- 6.2 ng/ml and 17.4 +/- 7.8 ng/ml for the 14 control subjects. In the face of markedly elevated serum AP levels in the rickets subjects, all of the serum OC values in the study fell within two standard deviations of the mean for normals. There was no association between serum OC and 1,25-(OH)2D in either the phosphopenic or the calciopenic group. CONCLUSION: These results show that serum osteocalcin levels are not elevated in all forms of active rickets and that, unlike serum alkaline phosphatase, serum osteocalcin cannot be used in the diagnosis of rickets.

Underestimation of Mycobacterium tuberculosis infection in HIV-infected subjects using reactivity to tuberculin and anergy panel.

BACKGROUND: This study aimed to evaluate purified protein derivative (PPD) reactivity and its interrelationship with anergy panel and CD4+ lymphocytes in HIV-infected subjects as compared to PPD reactivity in HIV-uninfected individuals in a tuberculosis endemic and high Bacillus Calmette-Guérin (BCG) coverage environment. METHODS: Clients of four Mexico City HIV detection centres were screened for HIV-1 antibodies (ELISA or haemagglutination, Western Blot); reactivity to PPD (Mantoux PPD, 5TU RT-23), Candida (1:1000, 0.1 ml), and tetanus toxoid (10Lf, 0.1 ml); and CD4+ T cells. Active tuberculosis was excluded. Informed consent was obtained. RESULTS: From 5130 clients 1168 subjects were enrolled; of these 801 (68.6%) were HIV positive. Reactivity to PPD among HIV-positive subjects was found in 174 (22%), 261 (32.6%), and 296 (37%), at PPD cutoff levels of > or =10 mm, > or =5 mm, and > or =2 mm as compared to 224 (61%) of 367 HIV-negative individuals' reactors to PPD (> or =10 mm) (P < 0.001). After exclusion of anergic individuals using two cutoff levels for cutaneous allergens (< or =2 mm and < or =5 mm), PPD reactivity between HIV-infected and uninfected individuals continued to be significantly different. Only HIV-infected individuals with CD4+ T cells > or =500 cells/mm3 had similar reactivity to PPD as HIV-uninfected individuals. Variables associated with PPD reactivity were CD4+ T cell counts, BCG scar, HIV infection and age. CONCLUSIONS: PPD reactivity was useful to diagnose tuberculosis infection only among HIV-infected individuals with CD4+ counts > or =500 cells/mm3. Among individuals with lower counts, lowering cutoff levels or using anergy panel did not permit comparable reactivity as that observed among HIV-uninfected individuals.

Transmission thresholds for dengue in terms of Aedes aegypti pupae per person with discussion of their utility in source reduction efforts.

The expense and ineffectiveness of drift-based insecticide aerosols to control dengue epidemics has led to suppression strategies based on eliminating larval breeding sites. With the notable but short-lived exceptions of Cuba and Singapore, these source reduction efforts have met with little documented success; failure has chiefly been attributed to inadequate participation of the communities involved. The present work attempts to estimate transmission thresholds for dengue based on an easily-derived statistic, the standing crop of Aedes aegypti pupae per person in the environment. We have developed these thresholds for use in the assessment of risk of transmission and to provide targets for the actual degree of suppression required to prevent or eliminate transmission in source reduction programs. The notion of thresholds is based on 2 concepts: the mass action principal-the course of an epidemic is dependent on the rate of contact between susceptible hosts and infectious vectors, and threshold theory-the introduction of a few infectious individuals into a community of susceptible individuals will not give rise to an outbreak unless the density of vectors exceeds a certain critical level. We use validated transmission models to estimate thresholds as a function of levels of pre-existing antibody levels in human populations, ambient air temperatures, and size and frequency of viral introduction. Threshold levels were estimated to range between about 0.5 and 1.5 Ae. aegypti pupae per person for ambient air temperatures of 28 degrees C and initial seroprevalences ranging between 0% to 67%. Surprisingly, the size of the viral introduction used in these studies, ranging between 1 and 12 infectious individuals per year, was not seen to significantly influence the magnitude of the threshold. From a control perspective, these results are not particularly encouraging. The ratio of Ae. aegypti pupae to human density has been observed in limited field studies to range between 0.3 and >60 in 25 sites in dengue-endemic or dengue-susceptible areas in the Caribbean, Central America, and Southeast Asia. If, for purposes of illustration, we assume an initial seroprevalence of 33%, the degree of suppression required to essentially eliminate the possibility of summertime transmission in Puerto Rico, Honduras, and Bangkok, Thailand was estimated to range between 10% and 83%; however in Mexico and Trinidad, reductions of >90% would be required. A clearer picture of the actual magnitude of the reductions required to eliminate the threat of transmission is provided by the ratio of the observed standing crop of Ae. aegypti pupae per person and the threshold. For example, in a site in Mayaguez, Puerto Rico, the ratio of observed and threshold was 1.7, meaning roughly that about 7 of every 17 breeding containers would have to be eliminated. For Reynosa, Mexico, with a ratio of approximately 10, 9 of every 10 containers would have to be eliminated. For sites in Trinidad with ratios averaging approximately 25, the elimination of 24 of every 25 would be required. With the exceptions of Cuba and Singapore, no published reports of sustained source reduction efforts have achieved anything near these levels of reductions in breeding containers. Practical advice on the use of thresholds is provided for operational control projects.

Attitudes and practices concerning the end of life: a comparison between physicians from the United States and from The Netherlands.

BACKGROUND: This study compares attitudes and practices concerning the end-of-life decisions between physicians in the United States and in the Netherlands, using the same set of questions. METHODS: A total of 152 physicians from Oregon and 67 from the Netherlands were interviewed using the same questions about (1) their attitudes toward increasing morphine with premature death as a likely consequence, physician-assisted suicide (PAS), and euthanasia; and (2) their involvement in cases of euthanasia, PAS, or the ending of life without an explicit request from the patient. Odds ratios, with 95% confidence intervals, were calculated to investigate relation between attitudes and various characteristics of the respondents. RESULTS: American physicians found euthanasia less often acceptable than the Dutch, but there was similarity in attitudes concerning increasing morphine and PAS. American physicians found increasing morphine and PAS more often acceptable in cases where patients were concerned about becoming a burden to their family. There was a discrepancy between the attitudes and practices of Dutch physicians concerning PAS. The proportions of physicians having practiced euthanasia, PAS, or ending of life without an explicit request from the patient differ more between the countries than do their attitudes, with American physicians having been involved in these practices less often than the Dutch. CONCLUSIONS: In this study of American and Dutch physicians, 2 important differences emerge: different attitudes toward the patient who is concerned over being a burden, and different frequency of euthanasia and PAS in the two countries.

Transmission thresholds for dengue in terms of Aedes aegypti pupae per person with discussion of their utility in source reduction efforts

The expense and ineffectiveness of drift-based insecticide aerosols to control dengue epidemics has led to suppression strategies based on eliminating larval breeding sites. With the notable but short-lived exceptions of Cuba and Singapore, these source reduction efforts have met with little documented success; failure has chiefly been attributed to inadequate participation of the communities involved. The present work attempts to estimate transmission thresholds for dengue based on an easily-derived statistic, the standing crop of Aedes aegypti pupae per person in the environment. We have developed these thresholds for use in the assessment of risk of transmission and to provide targets for the actual degree of suppression required to prevent or eliminate transmission in source reduction programs. The notion of thresholds is based on 2 concepts: the mass action principal-the course of an epidemic is dependent on the rate of contact between susceptible hosts and infectious vectors, and threshold theory-the introduction of a few infectious individuals into a community of susceptible individuals will not give rise to an outbreak unless the density of vectors exceeds a certain critical level. We use validated transmission models to estimate thresholds as a function of levels of pre-existing antibody levels in human populations, ambient air temperatures, and size and frequency of viral introduction. Threshold levels were estimated to range between about 0.5 and 1.5 Ae. aegypti pupae per person for ambient air temperatures of 28 degrees C and initial seroprevalences ranging between 0% to 67%. Surprisingly, the size of the viral introduction used in these studies, ranging between 1 and 12 infectious individuals per year, was not seen to significantly influence the magnitude of the threshold. From a control perspective, these results are not particularly encouraging. The ratio of Ae. aegypti pupae to human density has been observed in limited field studies to range between 0.3 and >60 in 25 sites in dengue-endemic or dengue-susceptible areas in the Caribbean, Central America, and Southeast Asia. If, for purposes of illustration, we assume an initial seroprevalence of 33%, the degree of suppression required to essentially eliminate the possibility of summertime transmission in Puerto Rico, Honduras, and Bangkok, Thailand was estimated to range between 10% and 83%; however in Mexico and Trinidad, reductions of >90% would be required. A clearer picture of the actual magnitude of the reductions required to eliminate the threat of transmission is provided by the ratio of the observed standing crop of Ae. aegypti pupae per person and the threshold. For example, in a site in Mayaguez, Puerto Rico, the ratio of observed and threshold was 1.7, meaning roughly that about 7 of every 17 breeding containers would have to be eliminated. For Reynosa, Mexico, with a ratio of approximately 10, 9 of every 10 containers would have to be eliminated. For sites in Trinidad with ratios averaging approximately 25, the elimination of 24 of every 25 would be required. With the exceptions of Cuba and Singapore, no published reports of sustained source reduction efforts have achieved anything near these levels of reductions in breeding containers. Practical advice on the use of thresholds is provided for operational control projects.

Stability of attitudes regarding physician-assisted suicide and euthanasia among oncology patients, physicians, and the general public.

PURPOSE: Attitudes regarding the ethics of physician-assisted suicide (PAS) and euthanasia have been examined in many cross-sectional studies. Stability of these attitudes has not been studied, and this is important in informing the dialog on PAS in this country. We evaluated the stability of attitudes regarding euthanasia and PAS among three cohorts. METHODS: Subjects included 593 respondents: 111 oncology patients, 324 oncologists, and 158 members of the general public. We conducted initial and follow-up interviews separated by 6 to 12 months by telephone, regarding acceptance of PAS and euthanasia in four different clinical vignettes. RESULTS: The proportion of respondents with stable responses to vignettes ranged from 69.2% to 94.8%. In comparison to patients and the general public, physicians had less stable responses concerning the PAS pain vignette (69.1% v 80.8%; P =.001) and more stable responses for all euthanasia vignettes (P <.001) except for pain. Over time, physicians were significantly more likely to change toward opposing PAS and euthanasia in all vignettes (P <.05). Characteristics previously associated with attitudes regarding PAS and euthanasia, such as Roman Catholic religion, were not predictive of stability. CONCLUSION: Up to one third of participants changed their attitudes regarding the ethical acceptability of PAS and euthanasia in their follow-up interview. This lack of consistency mandates careful interpretation of referendums and requests for physician-assisted suicide. Furthermore, in this study, we found that physicians are becoming increasingly opposed to PAS and euthanasia. The growing disparity between physicians and patients regarding the role of these practices is large enough to suggest possible conflicts in the delivery of end-of-life care.

Comparison of expression patterns and cell adhesion properties of the mouse biliary glycoproteins Bbgp1 and Bbgp2.

Biliary glycoproteins are members of the carcinoembryonic antigen (CEA) family and behave as cell adhesion molecules. The mouse genome contains two very similar Bgp genes, Bgp1 and Bgp2, whereas the human and rat genomes contain only one BGP gene. A Bgp2 isoform was previously identified as an alternative receptor for the mouse coronavirus mouse hepatitis virus. This isoform consists of two extracellular immunoglobulin domains, a transmembrane domain and a cytoplasmic tail of five amino acids. In this report, we have examined whether the Bgp2 gene can express other isoforms in different mouse tissues. We found only one other isoform, which has a long cytoplasmic tail of 73 amino acids. The long cytodomain of the Bgp2 protein is highly similar to that of the Bgp1/4L isoform. The Bgp2 protein is expressed in low amounts in kidney and in a rectal carcinoma cell line. Antibodies specific to Bgp2 detected a 42-kDa protein, which is expressed at the cell surface of these samples. Bgp2 was found by immunocytochemistry in smooth muscle layers of the kidney, the uterus, in gut mononuclear cells and in the crypt epithelia of intestinal tissues. Transfection studies showed that, in contrast with Bgp1, the Bgp2 glycoprotein was not directly involved in intercellular adhesion. However, this protein is found in the proliferative compartment of the intestinal crypts and in cells involved in immune recognition. This suggests that the Bgp2 protein represents a distinctive member of the CEA family; its unusual expression patterns in mouse tissues and the unique functions it may be fulfilling may provide novel clues about the multiple functions mediated by a common BGP protein in humans and rats.

Bulimia nervosa and alcohol dependence. A case report of a patient enrolled in a randomized controlled clinical trial.

Bulimia nervosa and alcohol use disorders frequently co-occur. A review of the literature, however, reveals a paucity of information on treatment of patients with these comorbid conditions. We present a case report of a 34-year-old Caucasian female with a 20-year history of bulimia nervosa with co-occurring alcohol dependence, who participated in a randomized placebo-controlled medication augmentation trial for bulimia nervosa. The patient served as a pilot subject who met the exclusionary criterion of alcohol dependence, but received all the assessment and intervention procedures of the clinical trial for bulimia nervosa. Despite double-blind random assignment to a placebo condition, the patient's symptoms of bulimia nervosa substantially improved over the course of the 5-week efficacy trial. We hypothesize that this improvement was due to concurrent abstinence from alcohol rather than a placebo effect.

The practice of euthanasia and physician-assisted suicide in the United States: adherence to proposed safeguards and effects on physicians.

CONTEXT: Despite intense debates about legalization, there are few data examining the details of actual euthanasia and physician-assisted suicide (PAS) cases in the United States. OBJECTIVE: To determine whether the practices of euthanasia and PAS are consistent with proposed safeguards and the effect on physicians of having performed euthanasia or PAS. DESIGN: Structured in-depth telephone interviews. SETTING AND PARTICIPANTS: Randomly selected oncologists in the United States. OUTCOME MEASURES: Adherence to primary and secondary safeguards for the practice of euthanasia and PAS; regret, comfort, and fear of prosecution from performing euthanasia or PAS. RESULTS: A total of 355 oncologists (72.6% response rate) were interviewed on euthanasia and PAS. On 2 screening questions, 56 oncologists (15.8%) reported participating in euthanasia or PAS; 53 oncologists (94.6% response rate) participated in in-depth interviews. Thirty-eight of 53 oncologists described clearly defined cases of euthanasia or PAS. Twenty-three patients (60.5%) both initiated and repeated their request for euthanasia or PAS, but 6 patients (15.8%) did not participate in the decision for euthanasia or PAS. Thirty-seven patients (97.4%) were experiencing unremitting pain or such poor physical functioning they could not perform self-care. Physicians sought consultation in 15 cases (39.5%). Overall, oncologists adhered to all 3 main safeguards in 13 cases (34.2%): (1) having the patient initiate and repeat the request for euthanasia or PAS, (2) ensuring the patient was experiencing extreme physical pain or suffering, and (3) consulting with a colleague. Those who adhered to the safeguards had known their patients longer and tended to be more religious. In 28 cases (73.7%), the family supported the decision. In all cases of pain, patients were receiving narcotic analgesia. Fifteen patients (39.5%) were enrolled in a hospice. While 19 oncologists (52.6%) received comfort from having helped a patient with euthanasia or PAS, 9 (23.7%) regretted having performed euthanasia or PAS, and 15 (39.5%) feared prosecution. CONCLUSIONS: Intractable pain or poor physical functioning seem to be nearly absolute requirements for physicians to perform euthanasia or PAS. Only one third of cases are performed consistently with proposed safeguards. For some patients, end-of-life care that includes opioid analgesia and hospice care does not obviate their desire for euthanasia or PAS. While the majority of physicians seem comforted by their actions, some experience adverse consequences from having performed euthanasia or PAS.

Bone disease in African children with slipped capital femoral epiphysis: histomorphometry of iliac crest biopsies.

African teenagers with slipped capital femoral epiphysis (SCFE) not infrequently also have genu valgum (knock-knee). Because we had previously demonstrated metabolic bone disease attributable to dietary calcium deficiency in black teenagers with genu valgum, we examined 29 black teenagers (15 male, 14 female) with SCFE for metabolic bone disease. Each patient had an iliac crest bone biopsy taken (after double tetracycline labeling) for routine histomorphometry, and blood and urine samples for bone biochemistry. Spinal bone mineral density was measured in 13 patients. Compared to reported data, we found our patients to be sexually more immature, older, at least as obese, and to have more severe and more frequently bilateral hip disease. Eighty percent of the children took dairy products only once or twice a week or less frequently, and 37.9% had genu valgum. Compared with race- and age-matched South Africans, bone biopsies in our patients showed lower bone volume (BV/TV, p = 0.0003), wall thickness (p = 0.0002), and trabecular thickness (Tb.Th, p = 0.0002), and a tendency to greater trabecular spacing (Tb.Sp, p = 0.053). Lower osteoid volume (OV/BV, p = 0.0001), osteoid surface (OS/BS, p = 0.0001), osteoid thickness (O.Th, p = 0.0002), double labeled surface (dLS/BS, p = 0.029), and bone formation rate (BFR/BS, p = 0.037) suggested poorer bone forming capacity in our patients. No evidence of hyperparathyroid bone disease or osteomalacia was found. BV/TV was below the reference range (14.2%) in 65.5% of cases; these patients had lower values for Tb.Th (p = 0.037) and Tb.N (p = 0.0003), greater Tb.Sp (p = 0.0002), a tendency to lower adjusted apposition rate (Aj.AR, p = 0.057), and had had less frequent intake of dairy products than those with normal BV/TV (p = 0.024). Furthermore, months since menarche correlated with histomorphometric variables BV/TV (r = 0.667, p = 0.009), Tb.Th (r = 0.745, p = 0.002), Tb.Sp (r = -0.549, p = 0.042), O.Th (r = 0.784, p = 0.0009), and Aj.AR (r = 0.549, p = 0.042). The correlation between Tb.Th and spinal bone mineral content (r = 0.656, p = 0.015) suggests that the reduced trabecular thickness reflected a generalized bone condition. A greater than normal proportion of patients had spinal bone mineral density values below -1 standard deviation (SD) of the mean (osteopenia) (p = 0.001). Patients tested for parathyroid hormone and 25-hydroxyvitamin D levels were found to have normal values. Parathyroid hormone correlated with Aj.AR (r = 0.661, p = 0.038) and serum phosphorus (r = -0.764, p = 0.010). We conclude that sexual immaturity and possibly past dietary calcium deficiency contributed to osteopenia, and that this, together with obesity, led to the development of more severe and more frequently bilateral SCFE in our patients than in reported series of black and white children.

Dynamics of the emergence of genetic resistance to biocides among asexual and sexual organisms.

A stochastic, agent based, evolutionary algorithm, modeling mating, reproduction, genetic variation, phenotypic expression and selection was used to study the dynamic interactions affecting a multiple-gene system. The results suggest that strong irreversible constraints affect the evolution of resistance to biocides. Resistant genes evolve differently in asexual organisms compared with sexual ones in response to various patterns of biocide applications. Asexual populations (viruses and bacteria) are less likely to develop genetic resistance in response to multiple pesticides or if pesticides are used at low doses, whereas sexual populations (insects for example) are more likely to become resistant to pesticides if susceptibility to the pesticide relates to mate selection. The adaptation of genes not related to the emergence of resistance will affect the dynamics of the evolution of resistance. Increasing the number of pesticides reduces the probability of developing resistance to any of them in asexual organisms but much less so in sexual organisms. Sequential applications of toxins, were slightly less efficient in slowing emergence of resistance compared with simultaneous application of a mix in both sexual and asexual organisms. Targeting only one sex of the pest speeds the development of resistance. The findings are consistent to most of the published analytical models but are closer to known experimental results, showing that nonlinear, agent based simulation models are more powerful in explaining complex processes.

Simulation of blacklegged tick (Acari:Ixodidae) population dynamics and transmission of Borrelia burgdorferi.

A model (LYMESIM) was developed for computer simulation of blacklegged tick, Ixodes scapularis Say, population dynamics and transmission of the Lyme disease agent. Borrelia burgdorferi Johnson. Schmid, Hyde, Steigerwalt & Brenner, LYMESIM simulates the effects of ambient temperature, saturation deficit, precipitation, habitat type, and host type and density on tick populations. Epidemiological parameters including host infectivity, tick infectivity, transovarial transmission, and transstadial transmission are included in the model to simulate transmission of the Lyme disease spirochete between vector ticks and vertebrate hosts. Validity of LYMESIM was established by comparing simulated and observed populations of immature I. scapularis on white-footed mice. Peromyscus leucopus, (Rafinesque), at 2 locations in Massachusetts. Validity also was indicated by comparisons of simulated and observed seasonality of blacklegged ticks in New York, Massachusetts, Florida, and Oklahoma-Arkansas. Further model validity was shown by correlation between simulated and observed numbers of immature ticks engorging on white-footed mice at 3 sites in Massachusetts. The model produced acceptable values for initial population growth rate, generation time, and 20-yr population density when historical meteorological data for 16 locations in eastern North America were used. Realistic rates of infection in ticks were produced for locations in the northeastern and northcentral United States. LYMESIM was used to study the effect of white-footed mouse and white-tailed deer, Odocoileus virginianus (Zimmerman), densities on tick density and infection rates. The model was also used to estimate tick density thresholds for maintenance of B. burgdorferi.