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Biomedical subjects

Erik C Jansen

Publications and source records attributed to Erik C Jansen.

4 recordsLinked to original sources
PubMed2005

Hyperbaric oxygen and radiotherapy.

BACKGROUND: Hyperbaric oxygen (HBO) therapy is the inhalation of 100% oxygen at a pressure of at least 1.5 atmospheres absolute (150 kPa). It uses oxygen as a drug by dissolving it in the plasma and delivering it to the tissues independent of hemoglobin. For a variety of organ systems, HBO is known to promote new vessel growth into areas with reduced oxygen tension due to poor vascularity, and therewith promotes wound healing and recovery of radiation-injured tissue. Furthermore, tumors may be sensitized to irradiation by raising intratumoral oxygen tensions. METHOD: A network of hyperbaric facilities exists in Europe, and a number of clinical studies are ongoing. The intergovernmental framework COST B14 action "Hyperbaric Oxygen Therapy" started in 1999. The main goal of the Working Group Oncology is preparation and actual implementation of prospective study protocols in the field of HBO and radiation oncology in Europe. RESULTS: In this paper a short overview on HBO is given and the following randomized clinical studies are presented: a) reirradiation of recurrent squamous cell carcinoma of the head and neck after HBO sensitization; b) role of HBO in enhancing radiosensitivity on glioblastoma multiforme; c) osseointegration in irradiated patients; adjunctive HBO to prevent implant failures; d) the role of HBO in the treatment of late irradiation sequelae in the pelvic region. The two radiosensitization protocols (a, b) allow a time interval between HBO and subsequent irradiation of 10-20 min. CONCLUSION: Recruitment of centers and patients is being strongly encouraged, detailed information is given on www.oxynet.org.

Combined Modality Therapy↗
PubMed2005

Pressure-equalizing earplugs do not prevent barotrauma on descent from 8000 ft cabin altitude.

INTRODUCTION: The aim of this study was to evaluate the effect of pressure-equalizing earplugs available in major airports and drugstores. No previous study has focused on preventing barotrauma using these earplugs. METHODS: Blinded and double-blinded, one type of pressure-equalizing earplugs (JetEars) was studied in 27 volunteers disposed to ear barotrauma. They acted as their own controls with an active earplug in one ear and a placebo earplug in the other ear at random. All were exposed to the same well-defined pressure profile for 1 h at 8000 ft, comparable to the environment in civil commercial air travel in a pressurized cabin. Satisfaction was assessed by questionnaire and objective results were evaluated prior to and after the pressure exposure by tympanometry and otoscopy using the Teed classification. RESULTS: The majority of the volunteers (78%) reported a pleasant noise-reducing feeling using the earplugs. However, 75% also experienced ear pain during descent. In comparing the middle ear pressure before and after pressurization, a decrease was found in ears with both active earplugs and placebo earplugs. No difference between the active and the placebo earplugs were found. Furthermore, after evaluation of the two groups of ears using otoscopy, no prevention of barotrauma was found. In fact, the ears using an active pressure-equalizing earplug scored significantly worse (p = 0.033). CONCLUSIONS: Feelings of noise reduction were reported, but no prevention of barotrauma could be demonstrated with the use of pressure-equalizing earplugs. Pressure-equalizing earplugs cannot be recommended in air travel for preventing ear barotrauma.

Acoustic Impedance Tests↗
PubMed2002

Refractive change during hyperbaric oxygen therapy. A clinical trial including ultrasound oculometry.

PURPOSE: To record changes in refraction and refractive parameters associated with a standard hyperbaric oxygen treatment protocol consisting of a 95 min session at > 95% oxygen at 2.5 atmospheres (ATA) given daily Monday to Friday, to a total of 30 sessions. PATIENTS AND METHODS: Seventeen of the 26 patients included were able to attend for ophthalmic assessment at time zero (to) and after 20 treatments (t20). Thirteen patients also had a post-treatment follow-up. Most patients were being treated for osteoradionecrosis after radiotherapy of ENT cancers, and drop-outs for the eye exam were common. Refraction was determined subjectively and by refractometry, before and after tropicamide 1% eyedrops. Refractive parameters were assessed by keratometry and by A-scan axial ultrasound measurement. RESULTS: Results are given for the 17 patients with to and t20 assessments. The induced refractive change ranged from 0 to 1.5 D. When observed, refractive changes were myopic in nature. The shift averaged 0.58 D according to the refractometer and 0.49 D as subjectively assessed, with corresponding median change values being 0.62 and 0.39 D. The differences between 0 D and these values, although small, were statistically highly significant. CONCLUSIONS: The refractive changes associated with hyperbaric oxygen therapy were smaller than the literature had led us to expect. No significant change in axial eye length measurements was found, and keratometry readings reflected only minimal change, although this was statistically significant on a 0.05 level. Therefore it is most likely that lens changes, whether in internal refractive indices or curvatures, accounted for the transitory shift towards more myopic/less hyperopic values.

Adult↗