Assessment of Mycobacterium tuberculosis pantothenate kinase vulnerability through target knockdown and mechanistically diverse inhibitors.

Pantothenate kinase (PanK) catalyzes the phosphorylation of pantothenate, the first committed and rate-limiting step toward coenzyme A (CoA) biosynthesis. In our earlier reports, we had established that the type I isoform encoded by the coaA gene is an essential pantothenate kinase in Mycobacterium tuberculosis, and this vital information was then exploited to screen large libraries for identification of mechanistically different classes of PanK inhibitors. The present report summarizes the synthesis and expansion efforts to understand the structure-activity relationships leading to the optimization of enzyme inhibition along with antimycobacterial activity. Additionally, we report the progression of two distinct classes of inhibitors, the triazoles, which are ATP competitors, and the biaryl acetic acids, with a mixed mode of inhibition. Cocrystallization studies provided evidence of these inhibitors binding to the enzyme. This was further substantiated with the biaryl acids having MIC against the wild-type M. tuberculosis strain and the subsequent establishment of a target link with an upshift in MIC in a strain overexpressing PanK. On the other hand, the ATP competitors had cellular activity only in a M. tuberculosis knockdown strain with reduced PanK expression levels. Additionally, in vitro and in vivo survival kinetic studies performed with a M. tuberculosis PanK (MtPanK) knockdown strain indicated that the target levels have to be significantly reduced to bring in growth inhibition. The dual approaches employed here thus established the poor vulnerability of PanK in M. tuberculosis.

Thiazolopyridone ureas as DNA gyrase B inhibitors: optimization of antitubercular activity and efficacy.

Scaffold hopping from the thiazolopyridine ureas led to thiazolopyridone ureas with potent antitubercular activity acting through inhibition of DNA GyrB ATPase activity. Structural diversity was introduced, by extension of substituents from the thiazolopyridone N-4 position, to access hydrophobic interactions in the ribose pocket of the ATP binding region of GyrB. Further optimization of hydrogen bond interactions with arginines in site-2 of GyrB active site pocket led to potent inhibition of the enzyme (IC50 2 nM) along with potent cellular activity (MIC=0.1 µM) against Mycobacterium tuberculosis (Mtb). Efficacy was demonstrated in an acute mouse model of tuberculosis on oral administration.

Molecular variants of HPV-16 associated with cervical cancer in Indian population.

Human papilloma virus is a causative factor in the etiology of cervical cancer with HPV16 being the most prevalent genotype associated with it. Intratype variations in oncogenic E6/E7 and capsid L1 proteins of HPV 16 besides being of phylogenetic importance, are associated with risk of viral persistence and progression. The objective of this multicentric study was to identify HPV-16 E6, E7 and L1 variants prevalent in India and their possible biological effects. Squamous cell cervical cancer biopsies were collected from 6 centres in India and examined for the presence of HPV 16. Variants of HPV-16 were characterized by full length sequence analysis of L1, E6 and E7 genes in 412 samples. Similar distribution of the variants was seen from the different centres/regions, with the European variant E350G being the most prevalent (58%), followed by American Asian variant (11.4%). Fifty six changes were seen in E6 region, 31 being nonsynonymous. The most frequent being L83V (72.3%), Q14H (13.1%) and H78Y (12.1%). Twenty-nine alterations were seen in E7 region, with 12 being nonsynonymous. The most frequent being F57V (9%). L1 region showed 204 changes, of which 67 were nonsynonymous. The most frequent being 448insS (100%), and 465delD (100%), H228D (94%), T292A (85%). The identified variants some new and some already reported can disrupt pentamer formation, transcriptional regulation of the virus, L1 protein interface interaction, B and T cell epitopes, p53 degradation, and thus their distribution is important for development of HPV diagnostics, vaccine, and for therapeutic purpose.

Nanostructured Cd(1-x)Mn(x)S films for spintronics and optoelectronic device applications: synthesis and characterization.

Nanostructured Cd(1-x )Mn(x)S (x = 0.3 and 0.4) films were prepared on glass substrates by thermal evaporation. All the films were deposited at 373 K and annealed at 473 K in high vacuum of 2 x 10(-6) mbar. The nanostructure films were characterized for composition, structure, morphology, optical and magnetic properties. All the films exhibited wurtzite structure of the host CdS material. AFM studies showed that all the films were in nanocrystalline form with the grain size varying in the range of 25-43 nm. The magnetic susceptibility increased sharply with Mn content 'x'.

EPR and susceptibility studies on (ZnS)1-x(MnTe)x powders.

(ZnS)1-x(MnTe)x luminescent powder samples with x=0.02, 0.05, 0.10, 0.15, 0.20 and 0.25 were prepared by solid-state reaction method. EPR spectra were recorded at room temperature (300K) in the frequency range 8.8-9.6GHz for samples of all compositions. The line width (DeltaH) and the number of spins increased with MnTe concentration. Room temperature dc magnetic susceptibility measurements were carried out using vibrating sample magnetometer. Susceptibility of the samples increased with MnTe content.

Optical and electrical studies of vapour phase grown Cd1-xCoxTe crystals.

The optical properties of vapour phase grown crystals of diluted magnetic semiconductor (DMS) Cd1-xCoxTe were investigated for x=0.001, 0.003, 0.005, 0.007 and 0.009. The reflectivity spectra exhibited a regular shift in the fundamental absorption edge (E0) with composition x. The reflectivity spectra for the present samples of Cd1-xCoxTe of all compositions exhibit broad bands at 5300 and 11,100cm(-1) due to the transitions of 4A2-->4T1 (F) and 4A2-->4T1 (P), respectively. Temperature dependence of resistivity revealed semiconducting behaviour of the samples. Hot probe test revealed that all the samples exhibited p-type conductivity.

ESR and photoluminescence properties of Cu doped ZnS nanoparticles.

Nanoparticles of Zn1-xCuxS with Cu concentrations of x=0.0, 0.1, 0.2, 0.3 and 0.4 were prepared by a co-precipitation reaction method from homogeneous solutions of zinc and copper salts. Both the ZnS and ZnS:Cu nanoparticles excited at about 370 nm exhibits a broad green emission band peaking around 491 nm, which confirms the characteristic feature of Zn2+ as well as Cu2+ ions as luminescent centers in the lattice. The TEM micrographs showed spherical morphology for ZnS nanocrystals and the average size of the particles was estimated to be around 8.5 nm. At liquid nitrogen temperature, ESR signal characteristic of Cu2+ ions was observed in samples of all concentrations. ESR spectra analysis also indicated that Cu2+ ions enter the host lattice by replacing Zn2+ ions with distorted tetrahedral site symmetry.

ac susceptibility and ESR studies on vapour phase grown Cd(1-x)Mn(x)Te crystals.

Single crystals of Cd(1-x)Mn(x)Te for x = 0.1, 0.2, 0.3, 0.4 and 0.5 were grown by a modified vapour phase growth technique. ac magnetic susceptibility studies were carried out in the temperature range 14-300 K. Both the real and the imaginary parts of susceptibility indicated the formation of spin-glass phase at low temperatures. ESR spectra were recorded at room temperature (300 K) at 9.4 GHz for samples of all compositions. The line width (DeltaH) increased with Mn content.

Near-total laryngectomy in advanced cancers of the larynx and pyriform sinus: a comparative study of morbidity and functional and oncological outcomes.

This prospective study, performed from 1991 to 1996, analyzes the differences in oncological safety, functional utility, and surgical morbidity in 14 advanced lesions of the larynx (10 T3 and 4 T4; 7 N+) and 40 pyriform sinus lesions (1 T2, 20T3, and 19 T4; 29 N+) subjected to Pearson near-total laryngectomy. The laryngeal cancer patients healed much faster, with a minimal wound complication rate of 28%, in comparison to the 68% rate encountered in the pyriform sinus cases (p < .05). The 3-year disease-free survival rate for the laryngeal cancers was 74%, while the 5-year survival rates for pyriform sinus cases were 66% for medial wall lesions and 54% for lateral wall lesions. Lung-powered shunt speech deemed qualitatively superior by acoustic analysis was obtained in 81% of the individuals (93% in laryngeal cases and 76% in pyriform sinus cases). Aspiration-free deglutition was achieved by 90% over periods ranging from 15 to 30 days. This study conclusively attests to the therapeutic efficacy of near-total laryngectomy for advanced lesions of the larynx and pyriform sinus that are unsuitable for radiotherapy, that are deemed too large or risky (because of aspiration) for partial laryngectomy, and that in the past would have merited total laryngectomy.

Mandibular metastasis in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) presenting initially as a bony metastasis is rare. Involvement of maxillofacial bones is even more rare and only 20 cases have been reported. A case of a 65-year-old male patient presenting with metastasis to the mandible from a primary HCC is described.

A rapid and sensitive extractive spectrophotometric determination of copper(II) in pharmaceutical and environmental samples using benzildithiosemicarbazone.

Benzildithiosemicarbazone (BDTSC) is proposed as a sensitive and selective analytical reagent for the extractive spectrophotometric determination of copper(II). BDTSC reacts with copper(II) in the pH range 1.0-7.0 to form a yellowish complex. Beer's law is obeyed in the concentration range 0.5-0.4 microg cm(-3). The yellowish Cu(II)-BDTSC complex in chloroform shows a maximum absorbance at 380 nm, with molar absorptivity and Sandell's sensitivity values of 1.63 x 10(4) dm3 mol(-1) cm(-1) and 0.00389 microg cm(-2), respectively. A repetition of the method is checked by finding the relative standard deviation (RSD) (n = 10), which is 0.6%. The composition of the Cu(II)-BDTSC complex is established as 1:1 by slope analysis, molar ratio and Asmus' methods. An excellent linearity with a correlation coefficient value of 0.98 is obtained for the Cu(II)-BDTSC complex. The instability constant of the complex calculated from Edmond and Birnbaum's method is 7.70 x 10(-4) and that of Asmus' method is 7.66 x 10(-4), at room temperature. The method is successfully employed for the determination copper(II) in pharmaceutical and environmental samples. The reliability of the method is assured by analyzing the standard alloys (BCS 5g, 10g, 19e, 78, 32a, 207 and 179) and by inter-comparison of experimental values, using an atomic absorption spectrometer.

Interjugular neck dissection and post-operative irradiation for neck control in advanced glottic cancers--are we justified?

At the Kidwai Memorial Institute of Oncology, advanced laryngeal cancers are subjected routinely to primary surgery and/or post-operative radiotherapy (RT). The surgery consists of wide field laryngectomy which entails total laryngectomy, ipsilateral/bilateral thyroid lobectomy, bilateral paratracheal clearance, and bilateral clearance of levels 2, 3 and 4 lymphatics. Post-operative RT is indicated in event of the following histopathological (HPE) situations to consolidate local-regional control: (1) T4 primary; (2) significant subglottic extension; and (3) jugular/paratracheal metastatic deposits. This prospective study highlights the therapeutic efficacy of this protocol at our centre in 45 consecutive T4/T3 glottic cancers and specifically evaluates the role of interjugular dissection and/or post-operative RT in prevention of regional recurrence. Fifty-two per cent of primary lesions needed a post-surgical upstaging as against 14 per cent of the neck lesions. Accordingly 91 per cent of the cases (41/45) qualified for post-operative RT and 82 per cent (37/41) complied with the prescribed schedule. Recurrent disease in the lateral neck was noted in 2/37 who received the prescribed schedule and 1/4 non-compliant cases; while a recurrent central neck disease was noted in 1/37 and 1/4 of these cases respectively. All cases were followed-up for a period of two years and 66 per cent of the evaluable cases for a period of five years. This study confirms conclusively that our treatment schedule yields extremely gratifying two-year local-regional control rates of 89 per cent which translates into a two and five-year actuarial survival rate of 92 and 70 per cent respectively.

EPR and susceptibility studies of Zn1-xMnxTe crystals at room temperature.

Single crystals of Zn1-xMnxTe for x = 0.1, 0.25, 0.45, 0.5 and 0.6 were prepared using vertical Bridgman technique. EPR (electron paramagnetic resonance) spectra were recorded at room temperature (303 K) between 0 and 6 kG magnetic field and range of frequency 8.8-9.6 GHz. As the concentration of Mn increases the line width (DeltaH) and the number of spins (Ns) were increased. Susceptibility studies were carried out at room temperature in the range of dc magnetic field 0-10 kG using vibrating sample magnetometer (VSM). Non-linear variation in susceptibility as a function of concentration (x) was observed and was explained on the basis of sp-d and d-d exchange interactions between Mn2+ ions and ZnTe lattice ions. Both EPR and susceptibility studies confirm the paramagnetic state of Zn1-xMnxTe system at RT.

Sero-prevalence of herpes simplex virus type-2 among cancer cervix patients.

Serum samples were collected from 140 cancer cervix patients aged between 25-60 years and also from 20 age matched, married, healthy women to serve as controls. These sera were tested for HSV-2 antibodies by ELISA test and HBsAg by RPHA test. HSV-2 antibodies were detected in 92 (65-71%) and HBsAg in 25 (17.8%) cancer cervix patients. Sera from control group were negative for HSV-2 antibodies and HBsAg.

Hepatocellular carcinoma metastatic to bones (Case report with review of literature).

A seventy year old man presented with bone pains. Investigation revealed a metastatic bone lesion in the humerus. The primary was found in the liver. The patient achieved good palliation with chemotherapy and radiotherapy and survived for one year.

Neck metastasis from an occult primary--the Kidwai experience.

This study highlights our treatment policy in 26 cases of epidermoid metastatic carcinoma in the neck from a primary deemed occult after exhaustive examination of the Upper Aero-digestive Tract (UADT). Planned Radical Neck Dissection (RND) and post-operative radiotherapy (RT) has been the favoured approach in all neck nodes deemed resectable and a loco-regional control rate of 64% was obtaining using this combined modality approach. Pre-operative RT was utilised in three cases with nodal disease of borderline resectability and loco-regional control was achieved in one case. Three cases of massive neck metastasis initially deemed unrectable became amenable to surgical salvage after Radical RT with concurrently administered chemotherapy. Only one of these remained disease free. Overall loco-regional control rate of 55 per cent could be achieved in 20 evaluable patients followed up for two years--three years (mean 30.5 months). Regional failures were noted in 25 per cent of patients while distant spread occurred in 15 per cent, thus accounting for an overall failure rate of 40 per cent. Manifest primaries were documented in 20 per cent, half of which could be salvaged and successfully controlled.

Nimotuzumab provides survival benefit to patients with inoperable advanced squamous cell carcinoma of the head and neck: a randomized, open-label, phase IIb, 5-year study in Indian patients.

OBJECTIVE: Overexpression of epidermal growth factor receptor (EGFR) in many cancers makes it an attractive therapeutic target. This study evaluated the clinical utility of nimotuzumab, a monoclonal anti-EGFR antibody, used concurrently with radiotherapy (RT) and chemoradiotherapy (CRT) in squamous cell carcinoma of the head and neck (SCCHN). METHODS: This open-label study randomized 92 treatment-naïve patients (1:1) with advanced SCCHN into chemoradiation (CRT ± nimotuzumab) or radiation (RT ± nimotuzumab) group by investigator's discretion; these were further randomized into CRT + nimotuzumab or CRT and RT + nimotuzumab or RT groups, respectively. Treatment included 6 cycles each of cisplatin (50 mg/week), nimotuzumab (200 mg/week), and RT (total dose, 60-66 Gy). Response (tumor size reduction) was assessed at Month 6 post-treatment and survival, at Month 60. RESULTS: Forty and 36 patients in the chemoradiation and radiation groups, respectively (intent-to-treat population) were evaluated. Overall response at Month 6 post-treatment was 100% with CRT + nimotuzumab, 70% with CRT, 76% with RT + nimotuzumab, and 37% with RT. At Month 60, overall survival was 57% with CRT + nimotuzumab, 26% with CRT (P = 0.03), 39% with RT + nimotuzumab, and 26% with RT (P > 0.05). Median overall survival was not reached for CRT + nimotuzumab; it was 21.94 months for CRT (P = 0.0078), 14.36 months for RT + nimotuzumab, and 12.78 months for RT (P = 0.45). Risk of death was 64% lower with CRT + nimotuzumab than with CRT (95%CI: 0.37, 1.56), and 24% lower with RT + nimotuzumab than with RT (95%CI: 0.16, 0.79). Thus nimotuzumab was safe and well tolerated with few mild to moderate self-limiting adverse events. CONCLUSION: Concurrent use of nimotuzumab with CRT/RT is safe and provides long-term survival benefit.

Coexpression of Notch1 and NF-kappaB signaling pathway components in human cervical cancer progression.

OBJECTIVES: Features of deregulated Notch1 signaling and NF-kappaB activation have independently been reported in cervical cancers. Here, we have extended these observations and examined both these pathways simultaneously in human cervical cancer tissue. Further, we have investigated the potential cross-talk between these pathways in a human cervical cancer derived cell line CaSki, which mirrors features of Notch activation as in the majority of human cervical cancers. METHODS: Cervical tissue samples were analyzed for the expression of Notch1, Jagged 1, Hes1, pAKT, NF-kappaB p50, NF-kappaB p65, IkappaB-alpha, Bcl-2, CyclinD1, Cdk9, c-Fos, and p53 by immunohistochemistry. A total of 352 samples were analyzed which included 69 normal cervical tissue, 132 preinvasive lesions and 151 squamous cell carcinomas of the uterine cervix. Dual immunofluorescent analysis was performed to evaluate the coexpression of Notch1 and NF-kappaB. Transcriptional reporter assays and xenografts were undertaken with CaSki cells. RESULTS: Features of Notch1 activation as measured by intracellular Notch1, high levels of Jagged1, Hes1 and Cdk9 were paralleled by nuclear translocation of both NF-kappaB p50 and p65 with target gene expression (IkappaB-alpha, Bcl-2, and CyclinD1) in human cervical cancer sections. Reporter assays in CaSki cells are consistent with Notch being an upstream regulator of NF-kappaB. Further, the xenografts recreate key aspects of human cancer tissue. CONCLUSIONS: Results from this study suggest that there is a co-activation of Notch1 and NF-kappaB signaling pathways at the cellular level in the majority of human cervical cancers, with Notch as an upstream regulator.