Biomedical subjects

C Birt

Publications and source records attributed to C Birt.

4 recordsLinked to original sources

PubMed2001

Prospective evaluation of eyelid function with gold weight implant and lower eyelid shortening for facial paralysis.

OBJECTIVES: To assess which signs and symptoms were relieved by gold weight implantation and which signs and symptoms persisted. DESIGN: Prospective observational cohort. SETTING: Tertiary care neurotology and oncology center. PATIENTS: Sixteen (4 males and 12 females) consecutive patients whose average age was 56 years (age range, 31-76 years). Inclusion criteria were gold weight implant, lagophthalmos of 2 mm or more, and a House-Brackmann score of 3 or less at the completion of follow-up. Mean follow-up was 13 months. INTERVENTIONS: Each patient received a gold weight implant. Six of these patients underwent a lower eyelid procedure. MAIN OUTCOME MEASURES: Surgical complications, static and dynamic lagophthalmos, static and dynamic corneal coverage, visual acuity, keratitis, topical treatment, and patient satisfaction. RESULTS: There were no extrusions. The preoperative mean lagophthalmos was 7.5 mm and the postoperative mean was 0.5 mm, (P<.001). Corneal coverage with eye closure before implantation was 73% and after implantation was 100%, (P<.001). Corneal coverage with normal (reflex) blink was less than 50% in 9 of 14 patients. When wearing correction, no patients had 20/20 visual acuity. The mean patient satisfaction score before the procedure was 3.5 and after was 7.1, (P<.001). Patient satisfaction was most closely related to visual acuity. The relationship was linear and statistically significant (P<.04). CONCLUSIONS: Gold weight implantation provides significant reduction in lagophthalmos and significant improvement in corneal coverage. But owing to delayed closure time and disrupted tear film, irritation may persist. As a result, some patients require ongoing topical treatment of the eye, which can compromise visual acuity.

Adult↗

PubMed2000

Probing peripheral and central cholinergic system responses.

OBJECTIVE: The pharmacological response to drugs that act on the cholinergic system of the iris has been used to predict deficits in central cholinergic functioning due to diseases such as Alzheimer's disease, yet correlations between central and peripheral responses have not been properly studied. This study assessed the effect of normal aging on (1) the tropicamide-induced increase in pupil diameter, and (2) the reversal of this effect with pilocarpine. Scopolamine was used as a positive control to detect age-dependent changes in central cholinergic functioning in the elderly. DESIGN: Randomized double-blind controlled trial. PARTICIPANTS: Ten healthy elderly (mean age 70) and 9 young (mean age 33) volunteers. INTERVENTIONS: Pupil diameter was monitored using a computerized infrared pupillometer over 4 hours. The study involved 4 sessions. In 1 session, tropicamide (20 microL, 0.01%) was administered to one eye and placebo to the other. In another session, tropicamide (20 microL, 0.01%) was administered to both eyes, followed 23 minutes later by the application of pilocarpine (20 microL, 0.1%) to one eye and placebo to the other. All eye drops were given in a randomized order. In 2 separate sessions, a single dose of scopolamine (0.5 mg, intravenously) or placebo was administered, and the effects on word recall were measured using the Buschke Selective Reminding Test over 2 hours. OUTCOME MEASURES: Pupil size at time points after administration of tropicamide and pilocarpine; scopolamine-induced impairment in word recall. RESULTS: There was no significant difference between elderly and young volunteers in pupillary response to tropicamide at any time point (p > 0.05). The elderly group had a significantly greater pilocarpine-induced net decrease in pupil size 85, 125, 165 and 215 minutes after administration, compared with the young group (p < 0.05). Compared with the young group, the elderly group had greater scopolamine-induced impairment in word recall 60, 90 and 120 minutes after administration (p < 0.05). CONCLUSION: There is an age-related pupillary response to pilocarpine that is not found with tropicamide. Thus, pilocarpine may be useful to assess variations in central cholinergic function in elderly patients.

Adolescent↗

PubMed1989

Induction reflex actions with intravenous nalbuphine as an adjunct to isoflurane.

Ninety unpremedicated patients undergoing mask anaesthesia were assigned to one of three groups according to the volatile anaesthetic and the acute intravenous premedication administered. Group I received saline placebo as premedication and halothane by inhalation. Group II received saline placebo and isoflurane by inhalation. Group III received nalbuphine 0.1 mg.kg-1 IV as premedication and isoflurance by inhalation. Mean time to loss of consciousness (71 sec) did not differ among groups. The dosage of thiopentone required to induce loss of consciousness was decreased by 15 per cent (from 3.9 to 3.3 mg.kg-1) by nalbuphine premedication (P less than 0.05), and time to induction of surgical anaesthesia using isoflurane was decreased by 15 per cent (P less than 0.05). The incidence of reflex actions (coughing, laryngospasm, breath holding, hiccoughs and movement) during induction was no different in the saline-premedicated halothane or isoflurane groups. Acute intravenous nalbuphine premedication decreased significantly the incidence of reflex actions during induction of isoflurane anaesthesia from 77 per cent to 37 per cent (P less than 0.02). Desaturation episodes (SaO2 less than 90 per cent) were more frequent with isoflurane inductions compared with halothane (55 per cent vs 17 per cent, P less than 0.01). Apnoeic episodes accounted for the majority of desaturations associated with nalbuphine premedication, while excitatory reflexes (coughing and laryngospasm) accounted for more desaturations with isoflurane alone.

Adult↗

PubMed1976

How many tastes are there for low concentration "sweet" and "sour" stimuli? - Threshold implications.

Ascending series of solutions of sucrose, glucose, and citric acid were tasted and detection and recognition thresholds were noted; subjects were also required to determine the number of taste sensations that occurred and their sequence of occurrence. It was found that subjects varied in their reports of the number of taste changes and hence potential criteria for detection and recognition. Even among those subjects who reported the same number of criteria there was little consistency as to which were actually chosen for detection and recognition. Some subjects even used an intensity change rather than a quality change to signal a threshold. They criterion can thus be seen to be a potential variable in threshold measurement, and criterion-free measures of sensitivity are recommended. Taste quality descriptions were also studied and a high proportion of novel descriptions was noted; it was hypothesised that this was due to the fact that subjects were not primed with traditional descriptive terms during the instructions.

Adolescent↗