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Biomedical subjects

M Laflamme

Publications and source records attributed to M Laflamme.

12 recordsLinked to original sources
PubMed2001

Effect of autonomic neurotransmitters on excitable gap composition in canine atrial flutter.

Atrial arrhythmias are believed to be influenced by autonomic nervous system tone. We evaluated the effects of sympathetic and parasympathetic activation on atrial flutter (AF1) by determining the effects of norepinephrine (NE) and acetylcholine (ACh) on the composition of the excitable gap. A model of reentry around the tricuspid valve was produced in 17 chloralose anesthetized dogs using a Y-shaped lesion in the intercaval area that extended to the right atrial appendage. Excitable gap characteristics were determined during AF1 by scanning diastole with a single premature extrastimulus at progressively shorter coupling intervals to define the reset-response curve. Measurements were made during a constant infusion of NE (15 microg/min) into the right coronary artery and repeated during ACh infusion (2 microg/min) following a 15 min recovery period. The excitable gap (27 +/- 1 ms) was significantly (P < 0.001) increased by NE (34 +/- 1 ms) and ACh (50 +/- 2 ms). The fully excitable portion (7 +/- 1 ms) was also significantly (P < 0.001) increased by NE (17 +/- 1 ms) and ACh (43 +/- 2 ms). We conclude that both neurotransmitters increase the safety margin of full excitability ahead of the wavefront, demonstrating that parasympathetic and sympathetic activation can facilitate the persistence of this refractory atrial arrhythmia.

Acetylcholine↗
PubMed1998

Current uses of virtual reality for children with disabilities.

Technological advances, including the use of virtual reality, have contributed enormously to improving the treatment, training, and quality of life of children with disabilities. This paper describes the advantages of VR for children with disabilities, how VR can minimize the effects of a disability, the role of VR in training and skills enhancement, and how social participation and the child's quality of life may be improved through the use of VR. Examples from published literature and Internet sites are given of current and completed projects which focus on improving the lives of children with disabilities. The research describing the efficacy of knowledge and skills transfer from a virtual environment to the real world are examined in relation to children with disabilities. Finally, the current limitations and future directions of VR for children with disabilities are considered.

Child↗
PubMed1997

Effects of procainamide on the excitable gap composition in a canine model of atrial flutter.

The effects of increasing concentrations of procainamide on the composition of the excitable gap were determined in a canine model of atrial flutter. Using the model of a Y-shaped lesion in the right atrium, reentry around the tricuspid valve was induced by burst pacing in 10 open-chest chloralose-anesthetized dogs. Diastole was scanned with a single premature stimulus and the relationship between the coupling interval of the premature beat and the return cycle length (CL) determined a reset-response curve that described the excitable gap. This was repeated up to the maximum flutter CL while infusing procainamide (30 mg/kg) over 1 h. Procainamide progressively prolonged the flutter CL from 131 +/- 21 (+/-SD) to 188 +/- 46 ms (p < 0.01) and the effective refractory period from 96 +/- 19 to 149 +/- 47 ms (p < 0.01). At peak plasma levels of 77 +/- 33 mumol/L the drug terminated flutter only in two dogs. Neither the duration (35 +/- 10 to 39 +/- 13 ms) nor the composition of the excitable gap changed on drug. A fully excitable portion (7 +/- 3 ms or 20 +/- 11% of the excitable gap) persisted on procainamide (7 +/- 3 ms or 19 +/- 9% of the excitable gap). It was concluded that procainamide prolongs the atrial flutter CL and the effective refractory period but does not change either the duration or composition of the excitable gap even at plasma concentrations that significantly exceed those recommended in man.

Action Potentials↗
PubMed1985

[You and digoxin].

Explore the source record for details and available documents.

Arrhythmias, Cardiac↗
PubMed1979

[Surgical correction of corneal astigmatism after corneal graft].

We performed Troutman's technique of corneal wedge resection in 6 patients who had substantial astigmatism after penetrating corneal grafts. The astigmatism was reduced by 5 to over 15 dioptres, and was stable for up to 36 months. The visual acuity was considerably improved in 5 of the 6 cases. However we could not neither predict the amount of correction nor the axis of the residual astigmatism with this technique. We stress the importance of using a keratometer when performing a penetrating corneal graft.

Adult↗
PubMedDate not supplied

Primary lymphoepithelioma-like carcinoma of the lung.

Primary lymphoepithelioma-like carcinoma (LELC) of the lung is a neoplasm seen most commonly in the nasopharynx of individuals from south China and Taiwan, and is strongly associated with the Epstein-Barr virus. The case of a 62-year-old Chinese man with a rare primary lung T2N1M0 LELC of the left lower lobe is presented. The lesion was further notable because of the presence of necrotizing granulomatous inflammation. The patient was treated with surgical resection. After it was determined that the neoplasm was of primary lung origin, adjunctive chemotherapy was initiated. The role of adjunctive chemotherapy in this setting is discussed.

Carcinoma, Non-Small-Cell Lung↗