Stapedotomy and its effect on hearing – our experience with 54 cases.

Introduction: This study reviews the cases of stapedotomy and evaluates its effectiveness at improving hearing loss in patients with otosclerosis. Materials and methods: Retrospective review of patients’ records who had clinical and audiometric diagnosis of otosclerosis from January to December 2012. Results: A total of 54 stapedotomy surgeries (52 unilateral and 1 bilateral surgeries) were received. Average post-operative ABG for 0.5, 1, 2 and 4 KHz showed that 61.1% had complete closure of ABG (ABG < 10 dB) compared with 1.6% preoperatively and 85.2% had closure of ABG to within 20dB compared with 4.7% preoperatively (t – 13.89, p = 0.000). More than 94% had hearing improvement and 81.5% had ABG closure greater than 10 dB postoperatively (mean gain 23.38 ± 12.37, t = 13.89, p = 0.000). A total of 13% complications were recorded with TM perforation (5.6%) being the commonest complication. Conclusion: Stapedotomy is an effective surgical procedure for the treatment of otosclerosis which leads to improvement in patients’ quality of life. A favorable hearing outcome can be obtained by the combination of experienced hands with minimal surgical trauma and appropriate surgical technique.

EFFECT OF BAP, NAA AND GA3, EITHER ALONE OR IN COMBINATION, ON MERISTEM CULTURE AND PLANTLET ESTABLISHMENT IN SWEET POTATO (CV BRONDAL)

In Zimbabwe, the average sweet potato yield (6 t/ha) is relatively low when compared to Asian counterparts (17 t/ha). These low crop yields have been blamed on weevil infestations and viral infections which account for 60-90% of sweet potato yield losses in Africa. Meristem tip culture, a Centre for Potato Improvement (CIP) initiated tissue culture technique, has been widely used to eradicate viruses from clonally propagated crops and has been noted to be one of the instrumental techniques that helped China to increase sweet potato yields. In an effort to adopt the meristem tip culture technique for the production of virus-free planting material of a local sweet potato (cv Brondal), a study was conducted to evaluate the effect of Benzylamino purine (BAP), 1-Naphthaleneacetic acid (NAA) and Gibberellic acid (GA3) (either alone or in combination) on cultured Brondal meristems. The different hormonal treatments were assessed on the following parameters: plantlet regenerative capacity, multiple plantlet production, shoot height, average leaf number per shoot and average node number per shoot, ten weeks after meristem culture. All treatments containing a combination of BAP (1 mg-L) and GA3 (at either 5 mg-L, 10 mg-L, or 20 mg-L) had a significantly (p<0.01) higher plantlet regenerative capacity of 33-66% when compared to other treatment combinations. Only treatments, 10 mg-L GA3 + 1 mg-L BAP and 20 mg-L GA3 + 1 mg-L BAP were capable of inducing multiple plantlet formation, producing an average of three plantlets/meristem and two plantlets/meristem respectively. Overall, treatment 10 mg-L GA3 + 1 mg-L BAP gave rise to significantly (p<0.01) taller shoots (20 mm) compared to the rest of the treatments used. For average leaf number per shoot, all GA3 treatments (5 mg-L, 10 mg-L, or 20 mg-L) supplemented with 1 mg-L BAP gave significantly (p<0.01) higher numbers of leaves (six leaves/shoot) than the rest of the treatments. Treatments 10 mg-L GA3 + 1 mg-L BAP and 20 mg-L GA3 + 1 mg-L BAP gave rise to the highest number of nodes per shoot, producing an average of three nodes per shoot. In sharp contrast to treatments containing a combination of BAP and GA3, all treatments containing a combination of BAP and NAA performed poorly in all parameters tested for plant regeneration of Brondal sweet potato variety. In conclusion, the best hormonal treatment for culturing Brondal meristems proved to be 10 mg-L GA3 + 1 mg-L BAP.