Application of microwave irradiation for the retrieval of masked antigenic sites to react with vimentin

Abstract EN

Objective: To improve immunoreactivity of the tumor marker vimentin in tissues over-fixed by formalin, using microwave radiation.

Methods: A total of 10 patients were studied; five cases with thyroid papillary carcinoma, 3 cases with rhabdomyosarcoma and two cases with salivary adenoma.

Two serial sections of 5?m thickness were cut off from paraffin blocks from the previously mentioned cases.

Sections were placed on 10 different pairs of slides coated with an adhesive (Vecta-bond, made by Vector Laboratories) to avoid tissue removal due to microwaving steps.

One of each pair of slides was incubated in 0.01M citrate buffer (pH 6) then heated by microwave radiation, while the other slide was left untreated.

Both slides were immunostained manually for vimentin using an Avidin Biotin Complex detection kit.

Results: The results showed that heating improved the detection of a specific positive reaction, while weak positive and negative results were seen in the untreated slides.

Heating of over-fixed slides helped in breaking cross-reacting bonds of proteins and unmasked the antigenic sites that are needed for antigen-antibody reaction.

Untreated slides still had masked antigenic sites thus giving faintly stained to negative results.

Conclusion: It is recommended to apply heat by microwave for 8-10 minutes on formalin-fixed tissues before immunostaining for vimentin to obtain optimal results.

MODIFIED MITCHELL’S OSTEOTOMY FOR THE TREATMENT OF HALLUX VALGUS.

EXPERIENCE AT KING HUSSEIN MEDICAL CENTER Mohamed Zaher, MD*, Issam Dahabra, MD* ABSTRACT Objective: To evaluate the outcome of modified Mitchell’s osteotomy for treatment of hallux valgus.

Methods: We reviewed the results of 69 patients (84 feet) in whom the modified Mitchell’s osteotomy with Y shape advancement of medial capsule, lateral adductor tenotomy and lateral capsule release, was done between 1993-2001 with an average follow up of 30 months (range 10-48 months).

Results: Radiographic and subjective results were evaluated.

Preoperative criteria included intermetatarsal angle of greater than 14 degrees (average 16.16), average metatarsophalangeal angle was 38.4 degrees (range 32-48 degrees) and painful Hallux valgus deformity.

The average postoperative intermetatarsal angle was 7.9 with relative correction of 8 degrees.

The average postoperative metatarsophalangeal angle was 9.2 degrees (range from 2-18).

Subjectively, all patients were satisfied with their results and stated they would have the procedure again.

There were no complications noted in the patients such as avascular necrosis, Hallux varus, and recurrence of deformity.

There were 6 delayed union cases for 6 months, and one infection.

Conclusion: The modified Mitchell’s osteotomy is an appropriate operative method that produces satisfactory results, and can be recommended in the treatment of moderate to severe Hallux valgus.