Neoplastic transformation of chronic ulcers in leprosy patients--a retrospective study of 23 consecutive cases.

A retrospective analysis of chronic ulcers among leprosy patients seen over the last 20 years yielded 23 cases of neoplastic transformation. It showed a peak at the sixth decade, an incidence of 3.66/100 among hospitalised ulcer cases and male/female ratio of 1.6:1. Borderline tuberculoid was the most common type of leprosy involved (40%). Squamous cell carcinoma was the most common neoplasia. Its usual site was plantar ulcers. Heel ulcers showed relatively greater predeliction for malignancy (38.5%). Histopathological proof of malignancy is desirable and that may require multiple biopsies. Metastasis is rare but potentially fatal. The surgical treatment must provide a functional, trouble-free limb. Forefoot or Lisfranc's amputation for distal third ulcers and below-knee amputation for large midfoot and ulcers are procedures of choice. Wide excision may be used in select cases.

Structural organization, amplification, deletion and rearrangements of DNA sequences associated with an unstable region of the chromosome of Streptomyces coelicolor A3(2).

The chromosome of Streptomyces coelicolor A3(2) carries unstable DNA sequences hybridising with DNA sequences from an unstable chromosomal region of the related species S. lividans. These S. coelicolor sequences are nearly identical to those of S. lividans TK23 in organisation but differ from those of S. lividans 66 TK64 which harbours a tandem duplication of these sequences. Southern hybridisations using heterologous probes and S. coelicolor DNA cleaved with a variety of restriction enzymes permitted us to construct a partial restriction map of the unstable region of the chromosome of S. coelicolor. Genetic analysis shows that the unstable region yields distinguishable variants with several distinct DNA rearrangements.