Biomedical subjects

K M Abell

Publications and source records attributed to K M Abell.

4 recordsLinked to original sources

PubMed1999

Eyelid kinematics following blepharoplasty.

PURPOSE: This study characterizes the effects of blepharoplasty on blink dynamics in subjects with dermatochalasis. The authors evaluate the hypothesis that orbicularis oculi removal and the consequent alterations in blink are potentially harmful consequences of blepharoplasty. METHODS: Sixteen patients were studied, before and after laser blepharoplasty, by a modified scleral search coil technique. Changes in lid position during blinks were recorded before surgery as well as 2 months, and 1 year postoperatively. Off-line analyses assessed blink down-phase amplitude, peak velocity, duration, and main sequence (peak velocity versus amplitude) relationships. RESULTS: Despite muscle resection, there was no significant compromise of mean blink down-phase amplitude, peak velocity, or main sequence following blepharoplasty. Mean blink duration was likewise unchanged at either follow-up session from the preoperative state. Our data show that upper lid blepharoplasty does not cause any lasting decrement in lid function in blinking. CONCLUSIONS: Blepharoplasty includes resection of a portion of the orbicularis oculi. It appears unlikely that the purposeful resection of preseptal portion of the orbicularis oculi that accompanies blepharoplasty is responsible for any functional complications such as dry eye.

Adult↗

PubMed1998

Efficacy of gold weight implants in facial nerve palsy: quantitative alterations in blinking.

Deficient eyelid closure is a major visual threat to patients with unresolved facial nerve palsy. Gold weight implants assisted eyelid closure in patients with paresis of the orbicularis oculi, ameliorating patient complaints of dry eye, excessive tearing, and corneal epithelial breakdown. We used dynamic measures to assess the efficacy of upper eyelid gold weight implantation surgery for facial nerve palsy. The search coil technique was used to record spontaneous blinks bilaterally in six patients, before and after unilateral gold weight implantations into the upper eyelid in severe facial nerve palsy. In uncomplicated facial nerve palsy, the amplitude of blink down-phases for the paretic eyelid was 28.6 +/- 5.7% of the amplitude of the contralateral, normal eyelid. Following corrective surgery, closure of the paretic eyelid improved to 42.6 +/- 7.5% (P < 0.05). There was not a commensurate increase in the peak velocity of blink down-phases, suggesting that gold weight effects are mediated by a passive improvement in blink dynamics.

Adult↗

PubMed1997

Catecholamine modulation of lymphocyte homing to lymphoid tissues.

Lymphocyte migration is an essential process for immune surveillance and for promoting cell-cell interactions necessary to generate an immune response. This report examined whether catecholamine prestimulation would alter the pattern of lymphocyte homing to spleen and lymph nodes in mice as determined by tracking fluorescently labeled cells. The results of cell sorter analysis showed that catecholamine-pretreated cells had increased accumulation in spleen and lymph nodes 1 and 2 h after i.v. injection. In addition, microscopic analysis showed that labeled cells migrated from the splenic red pulp to T-cell regions of the white pulp over a 2-h time course. Within the lymph nodes, labeled cells localized predominantly to the pericortex. Additional studies examined the migration of lymphocytes to lymphoid tissues of NGF-transgenic mice that have sympathetic hyperinnervation of spleen and peripheral lymph nodes. In contrast to the studies above, migration of T-cells from control mice to lymphoid tissues of the hyperinnervated mice was not different than that in control mice in most tissues. The accumulation of lymphocytes in lymphoid tissues is a balance between the influx of newly migrated cells and efflux back into the circulation. The studies in this report lend support to other studies showing catecholamine modulation of lymphocyte migration and homing, but it is a complex process about which much has yet to be understood.

Adrenergic beta-Agonists↗

PubMed1996

Catecholamines decrease lymphocyte adhesion to cytokine-activated endothelial cells.

Numerous studies have shown that catecholamines can modulate lymphocyte migration. This effect may be mediated in part by modulation of lymphocyte-endothelial cell interactions, which is dependent on adhesion molecules expressed on both of these cells. Our results show that catecholamines decreased T-cell binding to IL-1 activated endothelial cells in vitro. The decrease in adhesion was not mediated by a change in adhesion molecule expression as LFA-1 and VLA-4 expression on T-cells and ICAM-1 and VCAM-1 expression on endothelial cells were not changed by catecholamine stimulation. T-cells flatten and enlarge the area of surface contact as they adhere to endothelial cells. Image analysis of the number of T-cells bound and the amount of cell spreading over several time points suggests that catecholamines alter the kinetics of T-cell-endothelial cell adhesion. These results support the hypothesis that catecholamines can alter lymphocyte-endothelial interactions in vivo, which in turn would affect lymphocyte migration.

Catecholamines↗