Comparative analysis of immunohistochemistry and flow cytometry in the diagnosis of acute leukaemia: a single centre study

Background: Morphological evaluation and immunophenotyping are the major diagnostic modalities of acute leukaemia (AL). Although immunohistochemistry (IHC) and flow cytometry (FCM) are necessary for lineage assessment, but in many cases the use of these modalities alone might possess a diagnostic challenge. The study was aimed to analyse the diagnostic utility of IHC and FCM in the diagnosis of AL. Methods: This cross-sectional hospital-based study was done for one year and included 55 cases. Following peripheral blood examination and bone marrow study, IHC and FCM analysis was done using CD34, anti-MPO, CD3 and CD20. Results: There were 74.5% acute myeloid leukaemia (AML) and 25.5% acute lymphoblastic leukaemia (ALL) cases. By IHC, CD34 was positive in 94.5% cases, anti-MPO in 69.1%, CD3 in 3.6% and CD20 in 12.7% cases. But by FCM, CD34 was positive in 96.2% cases, anti-MPO in 61.5%, CD3 in 3.8% and CD20 in 19.3% cases. FCM could not be done for 3 cases as there was dry tap with pancytopenia and lineage assessment was done by IHC. On comparative analysis, CD34 was found to be better expressed by FCM. Anti-MPO and CD20 were better expressed by IHC and CD3 was equally expressed by both. Conclusions: IHC is an easy and cost-effective technique which gives an accurate characterization of the lineage and subtype of AL, especially in cases where use of FCM is limited such as cases with dry tap and pancytopenia and in limited resource centers.

Validity of mechanism of gene transfer in the process called conjugation in bacteria.

We have attempted a new evaluation of the process of conjugation in bacteria, because of some basic dissimilarities observed between this and that of eukaryotes, or plants and animals. Reference donor and recipient strains, widely used to prove conjugation in bacteria, were chosen; addition of DNase during the conjugation process, led to an unexpected but highly reproducible increase in the transconjugant colony counts (TCC; ca. > or = 1 log), when compared with that of the controls without DNase. Transconjugants were also obtained when the same live donors were substituted with the UV-killed ones although the TCC was very low initially. Contrarily, donors treated with DNA-intercalating agents, e.g. acridine orange or ethidium bromide, resulted in a complete failure to produce transconjugants. There was a quantitative relationship between the DNase used on donors and levels of DNA sugars/nucleotides/DNA, which possibly resulted from interaction between the DNase and DNA being present/produced on the donor surface. This may be indicative of what may actually happen in the donor-recipient mixtures in the conjugation test proper, where the recipient DNase may activate a donor DNA production cycle. The evidences presented did not suggest that the donor DNA in the conjugation process is actually vestibuled through any intercellular conjugation passages, and is susceptible to the action of DNase or the intercalating dyes.

Alterations in intracellular calcium during sepsis.

Tissue injury and/or infection produce significant alterations in intracellular calcium ion regulation. These alterations in cellular calcium has recently been studied following both short term and long term septic model which uses two types of gram-negative bacteria frequently encountered human abdominal sepsis. Changes in calcium flux as well as functional disturbances has been observed in the major organs, specially in skeletal muscle. The changes in calcium flux in different organs were studied using 45Ca exchange, 19F NMR study or by using calcium-fluorescence probes. Calcium-channel blockers attenuate the increased effects of calcium flux. Further anti-cytokines may be useful to prevent septic injury in tissues.

Longitudinal study on distribution of Phlebotomus argentipes sandflies at different heights in cattleshed.

Distribution of Ph. argentipes at three levels (level I, 0-0.91 m; level II, 0.91-1.82 m; and level III 1.82-2.74 m) above the ground in 6 cattlesheds was studied during July 1989 to June 1990. Of the 8044 Ph. argentipes caught, 3151 (39.2%), 3936 (48.9%) and 957 (11.9%) were from levels I, II, and III respectively. Both male and fed, half-fed, gravid and unfed female sandflies were found at all the three levels and in all the three seasons viz., rainy, winter and summer, of the year. The maximum height of occurrence of sandflies was 2.51 m (8.3 ft) above the ground level.

Chemical and pharmacological investigation of Solanum species of Brazil: a search for solasodine and other potentially useful therapeutic agents

A systematic search for solasodine, an important staring material for the partial synthesis of steroidal hormones as well as other potentially bioactive constituents of various Solanum species of Brazil has been undertaken. Thus, the fruits of S. paludosum, S. asperum, S. sessiliforum and Solanum sp. were found to contain significant amounts of solasodine. The root bark of S. paludosum which showe durare like activity yelded tomatidenol and another yet unidentified alkaloid responsible for the biological activity. The fruits of S. asperum yelded a new spirosolane alkaloid, solaparnaine. The stem bark of S. pseudo-quina showed convulsive and exitatory activity from which (25S)-isosolafloridine was identified as the active principle. In addition, the latter alkaloid was also found to show antimicrobial activity.