Consequences Of Treatment Strategies Research Articles

Optimal Drug Control under Risk of Drug Resistance – The Case of African Animal Trypanosomosis

AbstractWe examine two widely used treatment strategies for African animal trypanosomosis in West Africa: preventive drug control ex‐ante trypanosomosis infection and curative drug control ex‐post trypanosomosis infection. We investigate which combination of these alternative strategies is economically optimal for cattle farmers. We apply a dynamic optimisation framework to consider both the negative externality of drug resistance development and human behaviour. We develop a bio‐economic model to simulate the economic consequences of treatment strategies in a dynamic scenario that takes into account the interactions among the vector, host and livestock farmers. This model allows for the evolution of drug‐resistant trypanosomes through trypanocide misuse and simulates the observed behaviours of cattle farmers based on the elicited risk and time preferences of a sample of 202 cattle farmers in Mali and Burkina Faso. The results show that the private optimal mix of treatment strategies for a risk averse and patient farmer involves preventive treatment for susceptible cattle, supported by a small number of curative treatments for infected cattle. Compared with the treatment strategies observed in the field, this optimal mix of treatment strategies would save approximately 5% of the annual income of a livestock farmer in the study area and would reduce the prevalence of trypanosomosis. In addition, we demonstrate that a reduction in a farmer's risk aversion is associated with higher treatment rates that can avoid additional losses. By contrast, a decrease in a farmer's patience is related to lower treatment rates that thwart additional benefits. Our results suggest that individual risk and time preferences need to be considered in the development process of disease control interventions.

Scientific evidence reveals conjoined etiology in spinal deformation and the need for etiology based treatment. Insight in a trail

Effects of discongruent growth on the spine and central cord morphology gained attention in Orthopedics. If growth is dependent on exogenic factors and neuromuscular tension, therapy must focus on reversal of this. An extensive search on clues in existing literature was done. Goal was to formulate consequences for treatment strategies.

Micromorphological and micronanalytical characterization of stagnating and progressing root caries lesions

Root caries is the predominant disease of the tooth tissues in the elderly population and differs in progression and micromorphology from coronal dentin caries. Therefore, different clinical concepts are needed for the treatment of these progressing and arrested lesions. It was the aim of this study to investigate the three-dimensional structure and volume of stagnating and progressing root caries lesions and to determine the mineral composition of the different lesion zones to achieve a better understanding of the natural history of root caries lesion formation. Of 21 extracted human teeth of patients between 42 and 77 years of age with stagnating and progressing root caries lesions serial sections were cut and investigated with polarized light and scanning electron microscopy. From the polarized light micrographs 3D reconstructions were made to determine the volumes of the lesion zones and their relations expressed in a demineralization index (DI). With increasing size of the demineralizing zone the DI increased indicating an increase in the size of the translucent zone. The 3D reconstructions showed distinct differences between stagnating and progressing root caries lesions. In the hypermineralized translucent dentin not all dentin tubules were obliterated by intratubular dentin and within the translucent dentin scattered dead tracts were found. Electron dispersive X-ray (EDX) analysis showed that the intertubular dentin of the translucent dentin was also demineralized to a certain extent. The results indicate distinct morphological differences between progressing and stagnating root caries lesions which may have consequences for treatment strategies.

Secondary radiation damage as the main cause for unexpected volume effects: A histopathologic study of the parotid gland

To elucidate with a histopathological study the mechanism of region-dependent volume effects in the partly irradiated parotid gland of the rat. Wistar rats were locally X-irradiated with collimators with conformal radiation portals for 100% volume and 50% cranial/caudal partial volumes. Single doses up to 40 Gy were applied. Parotid saliva samples were collected, and the three lobes of the parotid gland were examined individually on the macro- and micromorphologic level up to 1 year after irradiation. Dose-dependent loss of gland weight was observed 1 year after total or partial X-irradiation. Weight loss of the glands correlated very well with loss of secretory function. Irradiating the cranial 50% volume (implicating a shielded lateral lobe) resulted in substantially more damage in terms of weight loss and loss of secretory function than 50% caudal irradiation (shielding the ventral and dorsal lobe). Histologic examinations of the glands 1 year after irradiation revealed that the shielded lateral lobe was severely affected, in contrast to the shielded ventral and dorsal lobes. Time studies showed that irradiation of the cranial 50% volume caused late development of secondary damage in the shielded lateral lobe, becoming manifest between 240 and 360 days after irradiation. The possible clinical significance of this finding is discussed. It is concluded that the observed region-dependent volume effect for late function loss in the rat parotid gland after partial irradiation is mainly caused by secondary events in the shielded lateral lobe. The most probable first step (primary radiation event) in the development of this secondary damage is radiation exposure to the hilus region (located between the ventral and dorsal lobe). By injuring major excretory ducts and supply routes for blood and nerves in this area, the facility system necessary for proper functioning of the nonexposed lateral lobe is seriously affected. The unexpected volume effect in the rat might have consequences for treatment strategies in radiotherapy, implicating not only salivary glands but also other organs with a seemingly homogeneous distribution of radiosensitive elements, a situation wherein volume effects have not been anticipated up to now.

Tyrosinaemia type I: considerations of treatment strategy and experiences with risk assessment, diet and transplantation.

The rapid development of new modes of treatment including organ transplantation, enzyme inhibition, enzyme replacement, liver cell transplantation and gene therapy necessitates knowledge about the results of all modes of treatment to allow decisions on treatment strategies. In hereditary tyrosinaemia type I, apart from the dietary treatment, both orthotopic liver transplantation (OLT) and treatment with 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC) have become available (Lindstedt et al 1992). However, this disease seems clinically very heterogeneous. Therefore, we should first attempt to categorize different clinical forms since treatment strategies may be quite different. Based on clinical heterogeneity, Halvorsen (1990) divided patients with tyrosinaemia into three forms - acute, subacute and chronic - but could not report the exact outcome on dietary treatment with possible consequences for treatment strategies. We have therefore investigated the clinical course on dietary treatment of our own patients and conducted an international survey on the clinical course of patients managed by dietary treatment and/or OLT, of which the results in part are described elsewhere (van Spronsen et al 1994). The results may enable us to compare the outcome on NTBC and to decide on treatment strategy in tyrosinaemia type I patients.