The pathophysiology of variant Creutzfeldt-Jacob disease: the hypotheses behind concerns for blood components and products.
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Blood Component Transfusion↗
Biomedical subjects
David J Roberts
Publications and source records attributed to David J Roberts.
Haemoglobinopathies and resistance to malaria.
The haemoglobinopathies have a celebrated role in the study of human genetics as the first examples of balanced polymorphisms described in human populations. Over the last 50 years, considerable evidence has been provided to show that these traits do confer protection from malaria. More recently, the underlying mechanisms of protection have been examined. This short review summarizes these studies and where possible shows how the putative mechanisms of protection may be linked to redox processes.
Animals↗
The origin of faeces by means of biomarker detection.
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Animals↗
Malaria, monocytes, macrophages and myeloid dendritic cells: sticking of infected erythrocytes switches off host cells.
The adhesive phenotypes expressed by Plasmodium-falciparum-infected erythrocytes were previously thought simply to permit sequestration of parasites in the peripheral circulation. Recent work has illuminated how falciparum-infected erythrocytes may modulate the function of monocytes, macrophages and myeloid dendritic cells through the action of haemozoin from digested haemoglobin and through adhesion of infected cells to their surface.
Animals↗
Amusement park injuries and deaths.
Media coverage of amusement park injuries has increased over the past several years, raising concern that amusement rides may be dangerous. Amusement park fatalities and increases in reported injuries have prompted proposed legislation to regulate the industry. Since 1979, the medical literature has published reports of 4 subdural hematomas, 4 internal carotid artery dissections, 2 vertebral artery dissections, 2 subarachnoid hemorrhages, 1 intraparenchymal hemorrhage, and 1 carotid artery thrombosis with stroke, all related to roller coaster rides. In this article, we review reports of amusement park injuries in the medical literature and Consumer Product Safety Commission data on the overall risk of injury. We also discuss the physics and the physiologic effects of roller coasters that may influence the type and severity of injuries. Although the risk of injury is low, emergency physicians are advised to include participation on thrill rides as part of their history, particularly when evaluating patients presenting with neurologic symptoms.
Biophysical Phenomena↗
Malaria and the red cell.
Because of the breakdown of malaria control programs, the constant emergence of drug resistant parasites, and, possibly, climatic changes malaria poses a major problem for the developing countries. In addition, because of the speed of international travel it is being seen with increasing frequency as an imported disease in non-tropical countries. This update explores recent information about the pathophysiology of the disease, its protean hematological manifestations, and how carrier frequencies for the common hemoglobin disorders have been maintained by relative resistance to the malarial parasite. In Section I, Dr. Louis Miller and colleagues consider recent information about the pathophysiology of malarial infection, including new information about interactions between the malarial parasite and vascular endothelium. In Section II, Dr. David Roberts discusses what is known about the complex interactions between red cell production and destruction that characterize the anemia of malaria, one of the commonest causes of anemia in tropical countries. In Section III, Dr. David Weatherall reviews recent studies on how the high gene frequencies of the thalassemias and hemoglobin variants have been maintained by heterozygote advantage against malaria and how malaria has shaped the genetic structure of human populations.
Adult↗
Effects of acetaldehyde on c-fos mRNA induction in the paraventricular nucleus following ethanol administration.
AIMS: The effect of acetaldehyde on c-fos mRNA expression in the paraventricular nucleus (PVN) of the rat was examined using in situ hybridization histochemistry. METHODS: Increases in acetaldehyde concentrations were induced using cyanamide (a potent inhibitor of aldehyde dehydrogenase), in the presence of two different doses of ethanol. Concentrations of blood ethanol and acetaldehyde were determined by head space gas chromatography. RESULTS: Neither cyanamide alone nor the low dose of ethanol (1 g/kg) alone increased c-fos expression in the PVN. However, the combination of cyanamide and low dose ethanol resulted in a significant and maximal increase in c-fos mRNA in the PVN. High dose ethanol (3 g/kg) resulted in a significant increase in c-fos mRNA. This stimulation also appeared maximal as there was no further increase in c-fos expression in the presence of cyanamide. CONCLUSIONS: These data suggest that acetaldehyde accumulation in blood has an important stimulatory effect on c-fos expression in the PVN at low ethanol concentrations. Furthermore, this stimulation of c-fos mRNA appears to be an either/or response: not activated in response to low dose ethanol, but maximally to high dose ethanol. These data also provide further evidence for a dissociation between the activation of c-fos and corticotrophin-releasing factor (CRF) mRNA in the PVN, as we have previously demonstrated that this dose of cyanamide alone is sufficient to evoke a sustained increase in plasma corticosterone and an increase in CRF mRNA.
Acetaldehyde↗
Seat-belt use by trauma center employees before and after a safety campaign.
OBJECTIVES: To determine whether employees of a regional trauma center wore seat belts any more often than did visitors to the medical center and residents of the state. To demonstrate whether an intensive safety campaign would improve seat-belt compliance among trauma center employees. To determine the duration of improvement. METHODS: Hospital employees and visitors were observed as they exited the medical center's parking ramps over a 3-month period. RESULTS: After a hospital-wide seat-belt campaign, employee compliance rose by 7.5%, to 81.5% at 14 days, but fell back to preintervention levels at one month (76.7%) and 3 months (77%) after the intervention. CONCLUSIONS: An intensive seat-belt safety campaign resulted in only modest and transient improvement in the rate of seat-belt use.
Adult↗