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Biomedical subjects

M Desrosiers

Publications and source records attributed to M Desrosiers.

43 records · Page 3Linked to original sources
PubMedDate not supplied

Alanine EPR dosimeter response in proton therapy beams.

We report a series of measurements directed to assess the suitability of alanine as a mailable dosimeter for dosimetry quality assurance of proton radiation therapy beams. These measurements include dose-response of alanine at 140 MeV, and comparison of response vs energy with a parallel plate ionization chamber. All irradiations were made at the Harvard Cyclotron Laboratory, and the dosimeters were read at NIST. The results encourage us that alanine could be expected to serve as a mailable dosimeter with systematic error due to differential energy response no greater than 3% when doses of 25 Gy are used.

Alanine↗
PubMedDate not supplied

Stimulation of T cells and induction of interferon by toxic shock syndrome toxin 1.

Toxic shock syndrome toxin 1 (TSST-1) is a potent immunomodulating substance isolated from Staphylococcus aureus strains associated with toxic shock syndrome (TSS). Flow cytometric analysis was used to compare scatter changes in several cell-surface phenotype markers on human mononuclear cells exposed in vitro to TSST-1 or to phytohemagglutinin, a lectin with similar effects on the immune response. The results showed differences between PHA and TSST-1 in the appearance of the tested T cell subset markers and of interleukin 2 receptors. In general, the stimulation of mononuclear cells by TSST-1 was slower than that by phytohemagglutinin. TSST-1 induced the production of interferon in cultures of murine spleen cells. By means of inhibition studies with specific antibodies to interferon, the interferon produced was characterized as the gamma type. Human mononuclear cells exposed to the toxin also produced gamma interferon, with levels similar to those induced by staphylococcal enterotoxin A, a known potent interferon inducer. The induction of gamma interferon by TSST-1 may play a role in the immunosuppression caused by TSST-1.

Adult↗
PubMedDate not supplied

Evaluation of two methods of self blood glucose monitoring by trained insulin-dependent diabetic adolescents outside the hospital.

We studied the accuracy of the Chemstrip bG and Glucometer systems in the self-monitoring of blood glucose by trained adolescents. The determinations were done at home with simultaneous collection of whole blood into capillary tubes (Sarstedt) which were later analyzed by a glucose-oxidase analyzer (Beckman Instruments). In both cases, there was an excellent correlation between laboratory concentrations and Chemstrip bG (r = 0.96, P less than 0.001) and Glucometer (r = 0.96, P less than 0.001). Comparisons made at 8 mo remained with the same degree of accuracy. There was a trend toward greater deviation with higher plasma glucose values. Well-trained patients can achieve sufficient accuracy to permit the use of either of the methods tested with similar results.

Adolescent↗
PubMedDate not supplied

Intensified insulin therapy in the type I diabetic adolescent: a controlled trial.

The effects of continuous subcutaneous insulin infusion (CSII), intensified conventional therapy (ICT), and a combination of CSII and ICT (CSII-ICT) on metabolic control were compared in a group of twenty type I diabetic adolescents who had previously failed to respond to twice-daily injections and home glucose monitoring. A marked improvement in control was observed when mean glycemia and glycosylated hemoglobin A1 (HbA1) were compared with conventional therapy (CT). In the course of CSII, a lower HbA1 (P less than 0.05) and mean capillary blood glucose (CBG) (P less than 0.04) were observed than during ICT and CSII-ICT. Acceptability of CSII was greater than that of ICT and CSII-ICT, with 50% of the patients opting for this therapy at the end of the 1-yr trial. The marked improvement of control observed under CSII for the group as a whole was maintained after 6 mo of completion of the study. Thus, it appears that in type I diabetic adolescents CSII is more effective and acceptable than ICT and CSII-ICT.

Adolescent↗
PubMedDate not supplied

Improved video documentation of endoscopic sinus surgery made possible with desktop digital video.

Endoscopic cameras in endoscopic sinus surgery (ESS) allow for easy video documentation of surgery. This often leads to the build-up of extensive videocassette libraries where the prospective viewer is subjected to a lengthy and cumbersome videotape search before accessing a sequence of interest. Footage is difficult to use for educational purposes. New techniques for storing, retrieving, and presenting ESS video footage were developed. Desktop computer systems were used to digitize video footage. Short video sequences containing highlights of interesting ESS cases were prepared using video-editing programs. The resulting images were stored in individual segments on recordable CD-ROM disks. This technique was used to archive all video footage from our ESS procedures for a 6-month period. Archiving footage on CD-ROM rather than videotape has made the storage of large quantities of information possible while now allowing for the random access of segment(s) of interest. It has simplified preparation of video projects, reduced production time 10-fold and has eliminated the need for professional video-editing services. These techniques have also been adapted for the development of an educational CD-ROM demonstrating the component steps of ESS, which can be played back on any CD-ROM-equipped computer.

CD-ROM↗