Utility of Line Probe Assay for the Early Detection of Multidrug-Resistant Pulmonary Tuberculosis

Background:

Despite endorsement of the line probe assay (LPA) for the diagnosis of drug-resistant pulmonary tuberculosis patients, there is limited data available on the performance of LPAs in India, especially from high burden states like Maharashtra, for the early diagnosis and detection of drug resistance, in order to initiate timely and appropriate treatment.

Objective:

To evaluate the utility of the line probe assay (LPA) for the early diagnosis of drug-resistant pulmonary tuberculosis as compared to the ‘Gold standard’ 1% proportion method (PM).

Materials and Methods:

A total of 687 patients suspected of pulmonary tuberculosis were screened. One hundred samples (95 sputum and 5 BAL), positive for Acid Fast Bacilli (AFB) by Ziehl Neelson (ZN) smears, were included in the study. Digested and decontaminated specimens were subjected directly to the LPA (Genotype MTBDR@ plus assay) and were processed in parallel using the conventional culture on the Lowenstein-Jensen (LJ) medium followed by drug susceptibility testing (DST) using the PM.

Results:

All the 100 samples gave interpretable results on LPA with a turnaround time of 24-48 hours as opposed to six to eight weeks taken by the 1% proportion method. Sensitivity for the detection of rifampicin, isoniazid, and multidrug resistance (MDR) was 98.1, 92.1, and 95%, respectively, with a specificity of 97.8% for rifampicin and 98.33% for MDR detection. It also had the additional advantage of allowing a study of mutation patterns.

Conclusions:

High performance characteristics and a short turnaround time makes LPA an excellent diagnostic tool, for an early and accurate diagnosis, in a high MDR- TB-prevalent region, as reflected from our data.

Isolation and Characterization of Trichoderma spp. for Antagonistic Activity Against Root Rot and Foliar Pathogens

Trichoderma, soil-borne filamentous fungi, are capable of parasitising several plant pathogenic fungi. Twelve isolates of Trichoderma spp. isolated from different locations of South Andaman were characterized for their cultural, morphological and antagonistic activity against soil borne and foliar borne pathogens. The sequencing of these isolates showed seven different species. The isolates revealed differential reaction patterns against the test pathogens viz., Sclerotium rolfsii, Colletotrichum gloeosporioides and C. capsici. However, the isolates, TND1, TWN1, TWC1, TGD1 and TSD1 were most effective in percentage inhibition of mycelial growth of test pathogens. Significant chitinase and β-1,3-glucanase activities of all Trichoderma isolates has been recorded in growth medium. T. viride was found with highest chitinase whereas T. harzianum was recorded with highest β-1,3-glucanase activities.

The cyclin-dependent kinase inhibitor p57(Kip2) is epigenetically regulated in carboplatin resistance and results in collateral sensitivity to the CDK inhibitor seliciclib in ovarian cancer

Background:

Carboplatin remains a first-line agent in the management of epithelial ovarian cancer (EOC). Unfortunately, platinum-resistant disease ultimately occurs in most patients. Using a novel EOC cell line with acquired resistance to carboplatin: PEO1CarbR, genome-wide micro-array profiling identified the cyclin-dependent kinase inhibitor p57^Kip2 as specifically downregulated in carboplatin resistance. Presently, we describe confirmation of these preliminary data with a variety of approaches.

Methods:

Cytotoxicity testing (MTT) and cell cycle blockade assessed drug responsiveness. Methylation specific PCR and pyrosequencing identified sites of promoter methylation in p57^Kip2. siRNA to p57^Kip2 was used to look at the changes in apoptosis of carboplatin treated EOC cells. EOC tissues (20 cases) were assessed for mRNA levels of p57^Kip2.

Results:

Carboplatin resistance was reversed using 5-aza-cytidine in vitro. Promoter methylation sites and preferential sensitivity to seliciclib were seen in PEO1CarbR cells. Silencing p57^Kip2 decreased the apoptotic response to the effects of platinum but produced sensitisation to seliciclib. EOC biopsies indicated an association of high levels of p57^Kip2mRNA with complete responses to chemotherapy and improved outcome.

Conclusion:

We conclude that p57^Kip2 is a candidate biomarker of platinum sensitivity/resistance in EOC and such cases may show preferential response to the cyclin-dependent kinase inhibitor seliciclib.

A Sensitive RP-HPLC Method for Simultaneous Estimation of Diethylcarbamazine and Levocetirizine in Tablet Formulation

A simple, sensitive and reproducible method was developed and validated for the simultaneous estimation of diethylcarbamazine and levocetirizine in its tablet formulation by reverse phase high performance liquid chromatography using Waters1515 HPLC with UV detector at the λ(max) of 224 nm, using Princeton Sphere-100 C(18) (250×4.6 mm. 5 μ) column. The mobile phase used was 20mM potassium dihydrogen orthophosphate buffer (pH: 3.2):acetonitrile (50:50 v/v) with isocratic flow (flow rate 1 ml/min) and the pH was adjusted with orthophosphoric acid. Losartan potassium was used as an internal standard. The compounds diethylcarbamazine, levocetirizine and losartan potassium were eluted at 2.12, 4.27 and 5.96 min, respectively. The peaks were eluted with better resolution. The method was accurate with assay values of 96.32 and 93.04% w/w, precise (%RSD) with intra-day 1.72 and 1.89 and inter-day 1.85 and 1.92, recoveries 102.86 and 101.1% w/w, which are very sensitive with limit of detections (LOD)'s 75, 50 ng/ml and limit of quantification (LOQ)'s 100, 75 ng/ml and linear with R(2) values 0.994 in the range of 5 to 30 μg/ml 0.1 to 1 μg/ml for diethylcarbamazine and levocetirizine, respectively. Hence this method can be applied for quantification of different formulations containing diethylcarbamazine and levocetirizine simultaneously.

Biology and field performance of gryon clavigrallae (Hymenoptera: Scelionidae), an egg parasitoid of Clavigralla spp. (Hemiptera: Coreidae) in India

The biology and impact of Gryon clavigrallae Mineo, an egg parasitoid of Clavigralla scutellaris Spinola and C. gibbosa (Westwood), was investigated. The calculated developmental threshold temperatures for females and males were 15.6 degrees C and 15.8 degrees C, respectively. Emergence exceeded 94% at temperatures between 22 and 30 degrees C. Adult females lived on average 28-96 days when fed with honey. Without food, adults lived < 6 days. Mean fecundity was 56.4 eggs per female. A significant trend of lower fecundity after longer periods of host deprivation was observed. Gryon clavigrallae females successfully oviposited in host eggs of all ages though eggs < 4 days old were preferred. Total host handling times were significantly longer on C. gibbosa eggs (23.5 min) than on C. scutellaris eggs (12.0 min). Females readily distinguished parasitized from non-parasitized host eggs. Superparasitism was observed when few or no unparasitized eggs were available. Eggs of the two Clavigralla species can be separated by surface structure and condition after eclosion. Clavigralla scutellaris laid significantly larger egg clusters than C. gibbosa (19.9 versus 10.5 eggs per cluster). Gryon clavigrallae was present as soon as the first Clavigralla spp. egg clusters were found on pigeonpea. The percentage of egg clusters parasitized increased early in the season with egg cluster density and remained high (up to 83%) despite fluctuations in host density. Overall, G. clavigrallae parasitized 40 and 58% of C. gibbosa and C. scutellaris eggs. The percentage of egg clusters parasitized and the number of eggs parasitized per cluster increased significantly with egg cluster size. The overall parasitoid sex ratio was highly female biased but varied with the number of eggs parasitized per cluster.