RSO interview with René Michel.
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Health Physics↗
Biomedical subjects
René Michel
Publications and source records attributed to René Michel.
Regression of the systemic vasculature to the lung after removal of pulmonary artery obstruction.
RATIONALE: Pulmonary artery occlusion stimulates angiogenesis in the systemic circulation of the ipsilateral lung and increases systemic- to-pulmonary blood flow. Whether this systemic neovascularization decreases after lung revascularization is unknown. OBJECTIVES: To assess the influence of lung revascularization on anatomy and flow of bronchial vessels supplying a chronically ischemic lung in piglets. METHODS: Piglets were studied before (control) and 5 wk after left pulmonary artery ligation and 5 wk after left pulmonary artery reimplantation into the pulmonary artery trunk. The systemic blood flow to the right and left lungs was measured using colored microspheres, and the bronchial vasculature was assessed using light-microscopic morphometry. Renal and total blood flow, systemic blood pressure, and pulmonary blood pressure were measured in each experimental condition. MEASUREMENTS AND MAIN RESULTS: Systemic blood flow to the left lung increased from 0.4 +/- 0.1 to 11.5 +/- 3.8 ml/min/g (p < 0.05) after left pulmonary artery ligation and returned toward the control value (1.2 +/- 0.6 ml/min/g) after revascularization, whereas it remained unchanged in the right lung. The number of bronchial vessels increased twofold in the ligated lung (p = 0.01), and did not decrease after reperfusion; however, vessel diameters decreased markedly. Renal and total blood flows, as well as mean pulmonary and systemic arterial pressures, were similar in the three experimental conditions. CONCLUSION: Revascularization after a period of left pulmonary artery occlusion normalizes the systemic blood flow to the left lung and induces partial loss of collateral vessels.
Animals↗
The carrot, not the stick: appetitive rather than aversive gustatory stimuli support associative olfactory learning in individually assayed Drosophila larvae.
The ability to learn is universal among animals; we investigate associative learning between odors and "tastants" in larval Drosophila melanogaster. As biologically important gustatory stimuli, like sugars, salts, or bitter substances have many behavioral functions, we investigate not only their reinforcing function, but also their response-modulating and response-releasing function. Concerning the response-releasing function, larvae are attracted by fructose and repelled by sodium chloride and quinine; also, fructose increases, but salt and quinine suppress feeding. However, none of these stimuli has a nonassociative, modulatory effect on olfactory choice behavior. Finally, only fructose but neither salt nor quinine has a reinforcing effect in associative olfactory learning. This implies that the response-releasing, response-modulating and reinforcing functions of these tastants are dissociated on the behavioral level. These results open the door to analyze how this dissociation is brought about on the cellular and molecular level; this should be facilitated by the cellular simplicity and genetic accessibility of the Drosophila larva.
Animals↗
Risk-informed, performance-based inspections at medical facilities.
During the past couple of years, radiation safety professionals have observed a significant change with regard to the inspection philosophy of regulators. The NRC and many Agreement State agencies have implemented a performance-based, risk-informed approach for inspecting medical Radiation Safety Programs. This new, less prescriptive approach originates from the necessity to produce safety benefits commensurate with their cost to the industry and still maintain health and safety performance. While compliance with regulatory requirements is important, regulatory agencies have been focusing on areas that provide greater safety benefit, such as protecting the radiation worker, members of the general public and the environment. This paper discusses simple and practical measures that may assist licensees in preparing for performance-based, risk informed inspections.
Employee Performance Appraisal↗
Induction of pulmonary angiogenesis by adenoviral-mediated gene transfer of vascular endothelial growth factor.
BACKGROUND: We hypothesized that gene transfer of vascular endothelial growth factor (VEGF) mediated by an adenovirus vector might induce pulmonary artery angiogenesis in a lamb model of pulmonary artery hypoplasia. METHODS: Thirteen fetal lambs had left pulmonary artery banding at 106 days of gestation. Following birth, 3 groups were divided: VEGF group (n = 5) and beta-GAL group (n = 4) received an adenoviral vector encoding respectively for human VEGF165 and for galactosidase A. A control group (n = 4) had neither gene nor virus. Viral suspensions were selectively instilled in the left bronchus 6.5 days after birth. Five nonoperated lambs constituted the normal group. Euthanasia was performed at 30 days of age. Gene transfer was confirmed by blue coloration of left lung obtained with Xgal solution in an additional experiment. Histomorphometric evaluation was performed. All groups were compared with ANOVA test and paired test was used to compare right and left lung in each animal. RESULTS: Left lung was similarly hypoplastic in all operated lambs. Left pulmonary artery hypoplasia present in all operated groups was significantly less pronounced in VEGF group. The number of pleural arteries was similarly increased in left lung of all operated lambs. Left lung arterial density was higher in VEGF group than in all other groups. The percentage of parenchyma of left lung was lower in beta-GAL group than in all others, partially returned to normal in VEGF group. CONCLUSIONS: In this model, transbronchial VEGF gene transfer induces pulmonary angiogenesis, proximal pulmonary artery growth and contributes to lung parenchyma recovery.
Adenoviridae↗
Radiation safety precautions for sentinel lymph node procedures.
Radiation safety professionals need guidelines for controlling occupational radiation doses and handling generated contaminated tissues from sentinel lymph node procedures involving 99mTc. Many healthcare facilities do not have formal controls in place, or they adopt policies that may be too restrictive or impractical. During accreditation inspections at healthcare facilities, agencies such as the College of American Pathology and the Joint Commission on the Accreditation of Healthcare Organizations occasionally raise questions about these issues. Inspectors expect to find formal policies to ensure these procedures are performed safely. The objective of this article is to review the basic radiation safety controls needed during sentinel lymph node procedures and to propose guidelines that may be used to control occupational radiation doses and handling of SLN contaminated tissues.
Decontamination↗
Preventing improper disposal of healthcare facility waste containing RAM.
Non-hazardous waste management facilities, which are not authorized to receive licensable radioactive material (RAM), periodically find contaminated waste in shipments from local healthcare facilities. As a consequence, many healthcare facilities are cited each year for losing control and/or improperly disposing of RAM at unauthorized disposal sites. Healthcare radiation safety professionals must ensure that effective measures are in place at their facilities to prevent RAM from inadvertently being included with non-radioactive waste shipments. The objective of this article is to assist in developing and implementing procedures to properly monitor and dispose of waste containing RAM. This article discusses, among other topics, the installation of portal monitors containing both visual and audible alarms to screen medical waste, instruction to individuals handling medical waste and emergency response procedures.
Health Facilities↗
Radiation safety compliance issues at affiliated institutions.
"Affiliation" may be defined as a collaborative interaction between two (or more) organizations in a spirit of mutual benefit through an equitable contribution of resources. Across the United States, hundreds of medical schools and healthcare organizations affiliate with one another for the enhancement of patient care, education, and research. Oftentimes, both parties in the affiliation have active clinical and research programs that involve the use of radioactive material (RAM). The combination of this close affiliation and use of radioactive material presents a number of challenging radiation safety compliance issues. It is important for radiation safety professionals (RSPs) employed by each affiliate to work together to ensure compliance with applicable regulatory requirements.
Cooperative Behavior↗
Implementation of an X-ray radiation protective equipment inspection program.
In order to comply with the requirements established by healthcare organization accrediting agencies, radiation protective equipment (e.g., lead aprons, gloves, and collars) utilized by x-ray workers must be periodically evaluated for damage. The objective of such evaluations is to identify and remove from service equipment bearing large holes, tears, etc., that could compromise the safety of individuals using this equipment. Many facilities are cited each year for failing to ensure the availability and integrity of such equipment. Unfortunately, written guidance on the proper implementation of inspection programs is not readily available. This paper was developed to assist healthcare organization safety personnel in establishing a radiation protective equipment inspection program at their facilities.
Equipment Failure↗
Radioactive drug research program audit checklist.
Many institutions conduct human research studies that involve the administration of radiopharmaceuticals. The Radiation Safety Officer (RSO) may be the person responsible for ensuring that such studies are performed safely and in compliance with applicable regulations. Sometimes, RSOs assigned this responsibility lack the knowledge and experience necessary to oversee such research activities. In an effort to assist RSOs unfamiliar with radioactive drug research regulations to establish an effective compliance program in this field, the authors developed a comprehensive audit checklist. Periodic use of this checklist may be effective in ensuring compliance with applicable regulations.
Drug and Narcotic Control↗