pH-induced reversible molecular self-assembly of perylene based imidazolate ester: a probable marker for biological species

Dianhydrides of perylene-3,4,9,10-tetracarboxylic acid (PTCDA) provide an excellent backbone for design and synthesis of various molecules of interest. Many water-soluble perylene derivatives with stimuli responded functionality being reported but there is few pH responded perylene derivatives were synthesized. The PTCDA derivatives so far synthesized are pH sensitive. These derivatives in an acid medium exist in its monomer form and undergo self-assembly with an increase in pH. In this paper, we report synthesis of pH-sensitive perylene based imidazolate ester, which exists in monomer form at pH 12 and undergo self-assembly with the decrease in pH contrary to the earlier reports. This phenomenon can be well explained for a probable marker in biological processes occurring specifically at pH 12.

Concurrent mycetoma and chromomycosis.

Chromoblastomycosis and Madura foot are chronic localised mycotic infection of the skin and subcutaneous tissue that follows the implantation of the fungi through minor trauma, mainly found in persons working outdoors on bare foot. In cases where both Madura and chromoblastomycosis are present, the treatment becomes difficult with low cure rates and frequent relapses. Here, we present such a very rare case of a 38-year-old cattle farmer who presented with verrucose nodules, tumefaction and multiple discharging nodules on the left lower 1/3 rd leg and foot since last 9 years. Direct KOH mount of the verrucose tissue showed Fonsecaea pedrosoi sclerotic muriform bodies and a biopsy of one granule discharging nodule demonstrated fungal mycetoma. He was put on tab. Itraconazole 200 mg o.d. and cotrimoxazole bid for 6 months with very little improvement. The rarity of this combination is most probably due to different geographical distribution.

Fnac study of histoid nodule: an early tool for diagnosis.

Histoid lesion, a variety of lepromatous leprosy, is due to alteration in the growth pattern of Mycobacterium leprae, possibly due to loss of immunity in localized areas. The distinction is based on cellular morphology by demonstrating pallisading arrangement of multi-layered spindle-shaped histocytes. Cytodiagnosis by fine needle aspiration cytology is therefore an early tool to recognize the histoid variety, differentiating it from a conventional LL module, as it is a simple and less traumatic procedure.

Prevalence of leprosy among household contacts of leprosy cases in western Orissa.

The prevalence rate of leprosy among household contacts is an important epidemiological indicator in the character and trend of the disease. During the period January 2001 to December 2002, families of 400 primary cases were studied to detect contact (secondary) cases. Seventy-two cases were detected from 54 families; of these 72 cases, 45 (62.5%) were in the paediatric age-group (0-14 years) and of these 45.8% belonged to 6-14 years group. Out of the 72 cases, there were more (58) of paucibacillary (PNL+I+TT+BT) cases. Secondary cases were significantly high when there was lepromatous type of leprosy in the family. The attack rate among those exposed to paucibacillary type (TT, BT) of leprosy, though much less, was still observed. The influence of duration of contact revealed that a maximum number of cases (N=43, 59.7%) acquired the disease during 0-6 years of contact. A majority of the patients belonged to low-income groups, were illiterate and lived in extended families. The father was the source case for most of the secondary cases (N=41, 57%). Conjugal leprosy was very rare. The results of the study points to the fact that PB leprosy is still a potential source of infection and cannot be ignored. It is important to evolve a hospital-based surveillance programme for contacts of leprosy patients since early detection and treatment of contacts are important measures for reducing the reservoir of infection in the community.