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Biomedical subjects

A P Santiago

Publications and source records attributed to A P Santiago.

8 recordsLinked to original sources
PubMed2000

Effect of plant lectins on Ustilago maydis in vitro.

Ustilago maydis is an edible parasitic basidiomycete, which specifically infects corn (Zea mays) and teocintle (Z. diploperennis). To characterise the interaction between the basidiomycete and its host organism, we tested the effect of plant lectins with well-known sugar specificity on the growth and germination of U. maydis spores. Lectins specific for N-acetyl-D-galactosamine, such as those from Dolichos biflorus and Phaseolus lunatus, and the wheatgerm agglutinin specific for N-acetyl-D-glucosamine inhibited spore germination, but were ineffective in modifying U. maydis cell growth. The galactose-specific lectin from the corn coleoptyle inhibited both germination and cell growth, while the lectin concanavalin A (mannose/glucose specific) activated spore germination and growth. Our results suggest that specific saccharide-containing receptors participate in regulating the growth and maturation of U. maydis spores.

Cell Division↗
PubMed1998

Dissociated vertical deviation and head tilts.

INTRODUCTION: The association of anomalous head posture and dissociated vertical deviation does not seem to be appreciated, as evidenced by the paucity of literature linking these two conditions. METHOD: The series describes 14 patients who had an anomalous head posture and dissociated vertical deviation. The assumed head tilts appeared to decrease the magnitude and improve the motor control of dissociated vertical deviation. RESULTS: Twelve of 14 patients tilted their heads contralateral to the eye with the dissociated vertical deviation, or away from the eye with a larger amount of dissociated vertical deviation if the disorder was bilateral. Two patients tilted their heads to the same side as the eye with the dissociated vertical deviation. Forced head tilt-testing in the opposite direction showed an increase in the magnitude of the dissociated vertical deviation or poorer control of the deviation. Dissociated vertical deviation was not related to oblique muscle dysfunction. Peripheral fusion was demonstrated in 10 patients, as evidenced by low-grade stereopsis or Worth 4 dot fusion at near. One patient did not show any demonstrable fusion with conventional tests. Another did not show evidence of stereopsis, but Worth 4 dot testing was not performed. Two other patients were too young to cooperate with sensory testing. Anomalous head posture was controlled or minimized after the control of the dissociated vertical deviation by surgery in four patients. Two patients showed improved stereopsis after surgery for dissociated vertical deviation. CONCLUSION: Dissociated vertical deviation should be included in the differential diagnosis of an ocular cause of head tilts. Forced contralateral head tilttesting will confirm whether dissociated vertical deviation is the cause if motor control of the dissociated vertical deviation worsens or becomes manifest rather than latent. The presence of an anomalous head posture in patients with dissociated vertical deviation can be improved with strabismus surgery.

Adult↗
PubMed1998

The paralimbal approach with deferred conjunctival closure for adjustable strabismus surgery.

Interest in the adjustable suture technique was renewed in the mid-1970s. The authors report a new modification of the fornix and limbal conjunctival approaches that combines the advantages of both. A paralimbal conjunctival incision is placed halfway between the limbus and the muscle insertion and directed parallel to the muscle insertion. This approach permits easy access to the rectus muscle. After the adjustable suture is temporarily secured with a bow-tie knot, the conjunctiva is partially closed using a loop suture over the muscle suture. An optional modification is the use of a "sweep suture" to break early adhesions at the time of adjustment. The adjustment procedure is performed at least 6 hours after the surgery. The conjunctiva is retracted as necessary for access to the muscle suture. If a sweep suture is used, this is first withdrawn before attempting any adjustment. After adjustment, the conjunctival loop suture is closed, covering the muscle suture. The sweep suture serves as a safeguard for what may otherwise be a difficult adjustment. This approach increases patient comfort after the surgery.

Conjunctiva↗
PubMed1997

Grave complications after superior oblique tenotomy or tenectomy for Brown syndrome.

INTRODUCTION: Superior oblique tenotomy or tenectomy was the preferred procedure for Brown syndrome for decades. Superior oblique palsy was reported as a complication, but the complex nature of this palsy and the difficulty in treating it was not emphasized. We documented cases with distressing symptoms of unilateral and bilateral superior oblique palsy after a free tenotomy or tenectomy of the superior oblique tendon for Brown syndrome. METHODS: Four cases referred for management of complex strabismus after superior oblique surgery for Brown syndrome were identified. Case histories, complications, and corresponding management are described in detail. RESULTS: All cases presented with bothersome symptomatic superior oblique palsy-incomitant vertical deviation with significant torsion, diplopia worse in functional down gaze, and anomalous head postures. Although reanastomoses of the superior oblique tendon was attempted in all cases,the procedure was modestly successful in only one case. Superior oblique palsy could not be reversed. After three procedures, Case 1 was orthotropic in primary, right, and left gaze but had a small intermittent tropia in down gaze. Case 2 underwent bilateral superior oblique operations. Despite a unilateral reanastomosed superior oblique tendon, hypertropia in down and left gaze and 15 degrees chin down position persisted. Case 3 showed correction of head tilt and a negative cover test 1 week after the second operation for iatrogenic superior oblique palsy, but stability of the procedure could not be ascertained. Case 4 had a successful attempt at reanastomosis and regained control of the vertical deviation as a hyperphoria. Both anomalous head posture and torsion improved. CONCLUSION: Superior oblique surgery for Brown syndrome may cause irreversible serious strabismus problems. Patients are left with distressing cyclovertical deviation worse in the functional position of gaze with significant torsional component that was resistant to therapy. Although adaptive mechanisms, such as an anomalous head posture, may develop, patients are left with a permanent disability that could not be reversed. One should scrupulously adhere to the indications for surgery in Brown syndrome. Preoperative assessment of superior oblique function is stressed. An alternative surgical procedure that is potentially reversible should be considered. This should include a reliable method to recover both ends of the tenotomized superior oblique tendon in case the procedure needs to be modified at a later date.

Child↗
PubMed1997

The effect of anterior transposition of the inferior oblique muscle on ocular torsion.

INTRODUCTION: The effects of anterior transposition of the inferior oblique on elevation in adduction have been studied, but changes in objective ocular torsion have not been investigated. METHODS: A prospective study on the effect of anterior transposition of the inferior oblique on objective torsion with use of fundus photography was undertaken in 24 eyes of 13 patients. The amount of oculartorsion was determined by measuring the angle formed by a horizontal line drawn across the geometric center of the disc and a second line connecting the geometric center to the foveola. RESULTS: The decrease in excyclotorsion at 6 to 8 weeks after surgery was 6.9+/-5.0 degrees (34%) (p = 0.006) and 2.8+/-4.4 degrees (13%) (not significant) after 10 weeks. An overall net change of 6.2+/-4.8 degrees (33%) was obtained after anterior transposition of the inferior oblique adjacent or anterior to the inferior rectus insertion (p = 0.006). Transpositions done 1 to 3 mm behind the inferior rectus insertion showed a negligible torsional change. Torsion where inferior oblique function normalized after anterior transposition of the inferior oblique (8.5+/-2.9 degrees) was not different from control, whereas torsion where inferior oblique function recurred after surgery (15.9+/-7.2) was significantly different from control (p = 0.002). Regression analysis showed that only preoperative inferior oblique overaction and preoperative degree of torsion predicted the change in torsion after anterior transposition of the inferior oblique. CONCLUSION: Anterior transposition of the inferior oblique muscle initially decreased objective excyclotorsion, but the effect decayed beyond 10 weeks. At least in the short term only anterior transposition of the inferior oblique muscle done adjacent or anterior to the inferior rectus insertion affected torsion.

Eye Diseases↗