An extensive review of arsenic dynamics and its distribution in soil-aqueous-rice plant systems in south and Southeast Asia with bibliographic and meta-data analysis

Millions of people worldwide are affected by arsenic (As) contamination, particularly in South and Southeast Asian countries, where large-scale dependence on the usage of As-contaminated groundwater in drinking and irrigation is a familiar practice. Rice (Oryza sativa) cultivation is commonly done in South and Southeast Asian countries as a preferable crop which takes up more As than any other cereals. The present article has performed a scientific meta-data analysis and extensive bibliometric analysis to demonstrate the research trend in global rice As contamination scenario in the timeframe of 1980-2023. This study identified that China contributes most with the maximum number of publications followed by India, USA, UK and Bangladesh. The two words 'arsenic' and 'rice' have been identified as the most dominant keywords used by the authors, found through co-occurrence cluster analysis with author keyword association study. The comprehensive perceptive attained about the factors affecting As load in plant tissue and the nature of the micro-environment augment the contamination of rice cultivars in the region. This extensive review analyses soil parameters through meta-data regression assessment that influence and control As dynamics in soil with its further loading into rice grains and presents that As content and OM are inversely related and slightly correlated to the pH increment of the soil. Additionally, irrigation and water management practices have been found as a potential modulator of soil As concentration and bioavailability, presented through a linear fit with 95% confidence interval method.

Practical consensus recommendations regarding the management of HER2 neu positive metastatic breast cancer

Metastatic breast cancer (MBC) is cancer that has spread from the breast to another part of the body or has come back in another distant location. Treatment options for MBC depend on several factors, including where the cancer has spread, the patient's overall health, and the levels of hormone receptors and HER2 in the tumour. Over-expression of HER2 is generally considered to be a negative prognostic feature because it accompanies an increase in breast cancer mortality. However, the development of agents that specifically target HER2 has improved the management of patients with these tumours.^{[7],[8],[9],[10]} This expert group used data from published literature, practical experience and opinion of a large group of academic oncologists to arrive at these practical consensus recommendations in regards with the use of these agents and the management of HER2 positive MBC for the benefit of community oncologists.

Practical consensus recommendations regarding the use of hormonal therapy in metastatic breast cancer

Metastatic breast cancer (MBC) is cancer that has spread from the breast to another part of the body or has come back in another distant location. Treatment options for MBC depend on several factors. One of these factors is the levels of hormone receptors (HRs) in the tumor. Cancers with high levels of HRs, called HR-positive, use the hormones estrogen and progesterone to grow and spread. Hormonal therapy is a type of treatment specifically for HR-positive breast cancer. This expert group used data from published literature, practical experience and opinion of a large group of academic oncologists to arrive at these practical consensus recommendations in regards with the use of hormonal therapy and the management of HR-positive MBC for the benefit of community oncologists.

Evolving multidisciplinary treatment of squamous cell carcinoma of the head and neck in India✰

In this article, we highlight the evolution of a multimodal approach in the overall management of squamous cell carcinoma of the head and neck (SCCHN) in India; present advances in technology (newer surgical techniques), novel medical and radiotherapy (RT) approaches; review their roles for an integrated approach for treating SCCHN and discuss the current role of immunotherapy in SCCHN. For locally advanced (LA) SCCHN, the multidisciplinary approach includes surgery followed by RT, with or without chemotherapy (CT) or concurrent chemoradiotherapy. Improved surgical techniques of reconstruction and voice-preservation are being implemented. Advanced forms of high-precision conformal techniques like intensity-modulated radiotherapy are used to deliver highly conformal doses to tumors, sparing the surrounding normal tissue. Compared with RT alone, novel CT regimens and targeted therapeutic agents have the potential to improve locoregional control and survival and reduce treatment-induced toxicities. Several clinical trials have demonstrated efficacy, safety, and quality of life benefits of adding cetuximab to RT regimens in LASCCHN. Studies have also suggested a cetuximab-related laryngeal preservation benefit. At progression, platinum-based CT combined with cetuximab (a monoclonal anti-epidermal growth factor receptor antibody) is the only validated option available as the first-line therapy. Thus, an integrated multidisciplinary approach plays a key role in maximizing patient outcomes, reduction in treatment related morbidities that consequently impact quality of life of survivors.

Practical recommendation for rash and diarrhea management in Indian patients treated with tyrosine kinase inhibitors for the treatment of non-small cell lung cancer

Tyrosine kinase inhibitors (TKIs) are a pharmaceutical class of small molecules, orally available with manageable safety profile, approved worldwide for the treatment of several neoplasms, including lung, breast, kidney and pancreatic cancer as well as gastro-intestinal stromal tumours and chronic myeloid leukaemia. In recent years, management of lung cancer has been moving towards molecular-guided treatment, and the best example of this new approach is the use of the tyrosine kinase inhibitors (TKIs) in patients with mutations in the epidermal growth factor receptor (EGFR). The identification of molecular predictors of response can allow the selection of patients who will be the most likely to respond to these tyrosine kinase inhibitors (TKIs). Gastrointestinal (GI) adverse events (AEs) are frequently observed in patients receiving EGFR tyrosine kinase inhibitor therapy and are most impactful on the patient's quality of life. Dermatologic side effects are also relatively common among patients treated with EGFR inhibitors. Evidence has emerged in recent years to suggest that the incidence and severity of rash, positively correlated with response to treatment.These skin disorders are generally mild or moderate in severity and can be managed by appropriate interventions or by reducing or interrupting the dose. Appropriate and timely management make it possible to continue a patient's quality of life and maintain compliance; however if these adverse events (AEs) are not managed appropriately, and become more severe, treatment cessation may be warranted compromising clinical outcome. Strategies to improve the assessment and management of TKI related skin AEs are therefore essential to ensure compliance with TKI therapy, thereby enabling patients to achieve optimal benefits. This article provides a consensus on practical recommendation for the prevention and management of diarrhoea and rash in Non-Small Cell Lung Cancer (NSCLC) patients receiving TKIs.

Transient receptor potential vanilloid 5 (TRPV5), a highly Ca2+ -selective TRP channel in the rat brain: relevance to neuroendocrine regulation

Recent studies suggest an important role for transient receptor potential vanilloid (TRPV) ion channels in neural and neuroendocrine regulation. The TRPV subfamily consists of six members: TRPV1-6. While the neuroanatomical and functional correlates of TRPV1-4 have been studied extensively, relevant information about TRPV5 and TRPV6, which are highly selective for Ca²⁺ , is limited. We detected TRPV5 mRNA expression in the olfactory bulb, cortex, hypothalamus, hippocampus, midbrain, brainstem and cerebellum of the rat. TRPV5-immunoreactive neurones were conspicuously seen in the hypothalamic paraventricular (PVN), supraoptic (SON), accessory neurosecretory (ANS), supraoptic nucleus, retrochiasmatic part (SOR), arcuate (ARC) and medial tuberal nuclei, hippocampus, midbrain, brainstem and cerebellum. Glial cells also showed TRPV5-immunoreactivity. To test the neuroendocrine relevance of TRPV5, we focused on vasopressin, oxytocin and cocaine- and amphetamine-regulated transcript (CART) as representative candidate markers with which TRPV5 may co-exist. In the hypothalamic neurones, co-expression of TRPV5 was observed with vasopressin (PVN: 50.73±3.82%; SON: 75.91±2.34%; ANS: 49.12±4.28%; SOR: 100%) and oxytocin (PVN: 6.88±1.21; SON: 63.34±5.69%; ANS: 20.4±4.14; SOR: 86.5±1.74%). While ARC neurones express oestrogen receptors, 17β-oestradiol regulates TRPV5, as well as CART neurones and astrocytes, in the ARC. Furthermore, ARC CART neurones are known to project to the preoptic area, and innervate and regulate GnRH neurones. Using double-immunofluorescence, glial fibrillary acidic protein-labelled astrocytes and the majority of CART neurones in the ARC showed TRPV5-immunoreactivity. Following iontophoresis of retrograde neuronal tracer, cholera toxin β (CtB) into the anteroventral periventricular nucleus and median preoptic nucleus, retrograde accumulation of CtB was observed in most TRPV5-equipped ARC CART neurones. Next, we determined the response of TRPV5-elements in the ARC during the oestrous cycle. Compared to pro-oestrus, a significant increase (P<.001) in the percentage of TRPV5-expressing CART neurones was observed during oestrus, metoestrus, and dioestrus. TRPV5-immunoreactivity in the astrocytes, however, showed a significant increase during metoestrus and dioestrus. We suggest that the TRPV5 ion channel may serve as an important regulator of neural and neuroendocrine pathways in the brain.

Clinical and epidemiological study of EGFR mutations and EML4-ALK fusion genes among Indian patients with adenocarcinoma of the lung

Background

Mutation in the tyrosine kinase domain of epidermal growth factor receptor (EGFR) is a common feature observed in lung adenocarcinoma. A fusion gene between echinoderm microtubule-associated protein-like 4 (EML4) and the intracellular domain of anaplastic lymphoma kinase (ALK), named EML4-ALK, has been identified in a subset of non-small-cell lung cancer (NSCLC) tumors. The objective of this study was to determine the prevalence of EGFR mutations and EML4-ALK fusions in Indian patients with NSCLC (adenocarcinoma) as well as evaluate their clinical characteristics.

Patients and methods

Patients with NSCLC, adenocarcinoma histology, whose tumors had been tested for EGFR mutational status, were considered for this study. ALK gene rearrangement was detected by fluorescence in situ hybridization using the Vysis ALK Break Apart Rearrangement Probe Kit. ALK mutation was tested in samples that were negative for EGFR mutation.

Results

A total of 500 NSCLC adenocarcinoma patients were enrolled across six centers. There were 337 (67.4%) men and 163 (32.6%) women with a median age of 58 years. One hundred and sixty-four (32.8%) blocks were positive for EGFR mutations, whereas 336 (67.2%) were EGFR wild-type. Of the 336 EGFR-negative blocks, EML4-ALK fusion gene was present in 15 (4.5%) patients, whereas 321 (95.5%) tumors were EML4-ALK negative. The overall incidence of EML4-ALK fusion gene was 3% (15/500).

Conclusion

The incidence of EGFR mutations (33%) in this Indian population is close to the reported incidence in Asian patients. EML4-ALK gene fusions are present in lung adenocarcinomas from Indian patients, and the 3% incidence of EML4-ALK gene fusion in EGFR mutation-negative cases is similar to what has been observed in other Western and Asian populations. The mutual exclusivity of EML4-ALK and EGFR mutations suggests implementation of biomarker testing for tumors harboring ALK rearrangements in order to identify patients that can benefit from newer targeted therapies.

Kinetics of the Oxidation of Aliphatic Aldehydes by Chromic Acid

The kinetics of chromic acid oxidation of propanaldehyde, butyraldehyde and isobutyraldehyde in aq. acetic acid have been studied. The product of the oxidation is the corresponding carboxylic acid. The reaction is of first order with respect to each the acid chromate ion, HCrO4 ⊖, and the aldehyde but of second order to hydrogen ion. The rate increases with proportion of acetic acid in the solution. The activation parameters for the oxidation and enolisation reactions have been evaluated. The rate of enolisation under similar condition is less than that of oxidation. A mechanism in which the first step is the rapid reversible formation of a chromate ester followed by a hydrideion transfer in the rate determining step has been suggested.

Arsenic uptake by Lemna minor in hydroponic system

Arsenic is hazardous and causes several ill effects on human beings. Phytoremediation is the use of aquatic plants for the removal of toxic pollutants from external media. In the present research work, the removal efficiency as well as the arsenic uptake capacity of duckweed Lemna minor has been studied. Arsenic concentration in water samples and plant biomass were determined by AAS. The relative growth factor of Lemna minor was determined. The duckweed had potential to remove as well as uptake arsenic from the aqueous medium. Maximum removal of more than 70% arsenic was achieved atinitial concentration of 0.5 mg/1 arsenic on 15th day of experimental period of 22 days. Removal percentage was found to decrease with the increase in initial concentration. From BCF value, Lemna minor was found to be a hyperaccumulator of arsenic at initial concentration of 0.5 mg/L, such that accumulation decreased with increase in initial arsenic concentration.

P5-06-01: Gene Expression Analysis of Resistance to Bevacizumab in a VEGF-Reinforced Xenograft Model of ER-Positive Breast Cancer

Background: Bevacizumab, a monoclonal antibody targeting vascular endothelial growth factor (VEGF), had promising therapeutic efficacy in breast cancer. However, intrinsic or acquired resistance is common in the clinic. To improve our understanding of the underlying mechanisms of resistance to bevacizumab (BEV), we report the gene expression analysis of resistance to bevacizumab in a VEGF-overexpressing xenograft model of ER-positive breast cancer.

Methods: We developed a nude mouse xenograft model of resistance to anti-VEGF therapy with BEV in which MCF-7 control (ML20) or MCF-7 VEGF (MV165) transfectants were implanted in mammary fat pads, allowed to grow, then treated with BEV, with collection of tumor at early or late time points (while responding (R) to or progressing (NR) on anti-VEGF therapy). To elucidate differentially expressed gene profiling associated with tumor resistance to BEV, we performed whole-genome gene expression analysis (Human WG-6v2 Expression Beadchips, Illumina) and miRNA profiling (TaqMan ***ArrayHuman MicroRNAA+B Cards Set v3.0, Applied Biosystems). Validation of the chosen genes was performed using quantitative real-time RT-PCR (qRT-PCR).

Results: Gene expression analysis revealed differentially regulated genes in the MV165-NR group compared with the MV165-R group. Among the significant genes, Follistatin (FST) and HEY2 were the top genes upregulated in NR compared to R by ANOVA. Expression of HEY2 is induced by the Notch signaling pathway. Using qRT-PCR, we validated the expression of FST and Notch in our system. FST was significantly decreased (Fold change= −3.2; P=0.03) in the R group compared with vehicle in MV165 xenografts. In contrast to R group, FST was upregulated significantly (Fold change= 9.3; P=0.05) in the NR group. Notch4 displayed increased levels of expression in NR group, but it did not reach significance (P=0.23). In addition, correlation of mRNA and miRNA profiles showed that miRNAs targeting FST and Notch4 were differentially regulated in NR group compared to R group in MV165 xenograft tumors. Among the miRNAs, TGF-β-induced oncomiR miR-181a is up-regulated in NR and targets both FST and Notch4. Other miRNAs that target both Notch4 and FST include miR-1, miR-133a, miR-133b, and mir-449b. Conclusion: Our data serve as a potential mechanistic explanation for acquired resistance to bevacizumab. These data may shed light on the transitory effect of BEV observed in the E2100 firstline metastatic breast cancer trial, where VEGF-targeted therapy prolongs progression-free survival in metastatic breast cancer without improving overall survival.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-06-01.

P2-13-01: Gene Profiling of Whole Blood May Identify Patients with BRCA Mutations

Background:The BRCA1 and the BRCA2 proteins play a role in DNA repair and confer genomic stability to the cell. Identifying BRCA mutation carriers has become an important tool for prevention as well as guiding therapy in cancer patients. We proposed to test the hypothesis that gene expression analysis of peripheral whole blood can reliably detect these mutations.

Materials and methods: Following IRB approval, 10cc of blood was collected from 36 women (BRCA1 (n=8), BRCA2 (n=9), Hereditary breast cancer without BRCA (FAM) (n=7), sporadic breast cancer (SPO) (n=11)). 3 of BRCA1 and 5 of BRCA2 samples were from women without cancer. Following RNA extraction (using the method described by Beekman et al) and quality assessment, Illumina® Whole-Genome DASL™ microarray (Human Ref-8 BeadChips) analysis was performed. The raw data was normalized and analyzed using Partek® Genomic Suite. Differentially expressed genes were identified using ANOVA analysis. Geneset specific supervised analysis was performed to visualize the inherent similarities and differences in the gene expression amongst different groups for 1) DNA repair and 2) Immune-system-related genes. Ingenuity Pathway Analysis (IPA) was performed to interpret the data in the context of biological processes, pathways and networks.

Results: Twenty-nine of the 87 immune-related genes were up-regulated in BRCA1 and BRCA2 groups compared to SPO or FAM groups; these included IL7R, CD53, CD2, CD48 and HLA-DRA. Twenty-five of the 79 DNA repair genes were up-regulated in BRCA1 and BRCA2; these included FANCC, RAD51L3, MSH2, MSH6 and PCNA. In IPA analysis, the comparison of BRCA1 vs. REST (BRCA2 + FAM + SPO) showed a strong immunologic signal, with the top altered biological processes including “Immunologic disease”, “Infection mechanism”, “Immune cell trafficking” and “cell-mediated immune response “. The top 5 canonical pathways also reflected a similar pattern and included “iCOS-iCOSL Signaling in T Helper Cells”, “OX40 Signaling Pathway”, “Calcium-induced T Lymphocyte”, “Apoptosis Regulation of IL-2 Expression in Activated and Anergic T Lymphocytes” and “Protein Ubiquitination Pathway”. When BRCA2 was compared with the REST (BRCA1 + FAM + SPO), a much weaker signal was noted with none of the canonical pathways being significantly altered. PAM analysis showed that a set of 16 genes could differentiate the BRCA patients from the rest with an error rate of 5%. Further validation of this geneset is being performed.

Conclusion: Gene profiling in whole blood may offer an easy, reliable and inexpensive way to identify patients with BRCA mutation. Further studies are currently underway to validate our results in a larger patient population.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-13-01.

P3-04-02: Bevacizumab Treatment Alters Intrinsic Subtypes in a VEGF-Reinforced Xenograft Model of ER-Positive Breast Cancer

Background: Anti-vascular endothelial growth factor (anti-VEGF) therapy improves disease-free but not overall survival in metastatic breast cancer. To seek further insight on resistance to anti-VEGF antibody bevacizumab (BEV) at the molecular level, we developed breast cancer xenograft models allowing comparison of tumor response at different time-points. Here we report the gene expression and miRNA analyses of response and non-response to BEV in these models.

Methods: MCF-7 cells transfected with control vector (ML20) or VEGF (MV165) were implanted into the mammary fat pads of athymic mice. Tumors from short-term treatment with BEV (3 weeks; Responders to BEV, R) or long-term treatment (8 weeks; Non-Responders, NR) or with vehicle control group (V) were subjected to whole-genome gene expression analysis (Human WG-6v2 Expression Beadchips, Illumina) and miRNA profiling (TaqMan ArrayHuman MicroRNA A+B Cards Set v3.0, Applied Biosystems).Validation of the chosen genes was performed using quantitative real-time RT-PCR (qRT-PCR) and Immunohistochemistry (IHC). Results: Short-term treatment to BEV (3 weeks; 5 mg/kg, i.p./twice weekly) inhibited primary tumor growth significantly in MV165 xenografts compared with vehicle control, whereas BEV treatment did not affect the tumor growth in the ML20 model. MV165 xenografts progressed after 8 weeks of BEV treatment. Gene set enrichment analysis (GSEA) revealed that luminal A-related gene sets were enriched in MV165-R compared to MV165-NR group including DESMEDT (ESR1), SMID_Breast_Cancer_Luminal_A_up, and MASSARWEH_ Tamoxifen_Resistance_ Down. Myoepithelial-specific gene sets were upregulated in both the R and NR groups compared with the vehicle group. qRT-PCR analysis showed that estrogen receptor alpha (ESR1) representative for luminal A decreased significantly in the MV-165-NR group (P=0.001) compared to vehicle. In contrast, Cytokeratin 5 (KRT5) levels increased significantly in both R (P=0.02) and NR (P=0.03) groups. In addition, KRT14 was upregulated in R (P= 0.04) and in NR (P=0.14) group in comparison with the vehicle group, suggesting the upregulation of myoepithelial phenotype specific to BEV treated MV165 model, but not ML20 model. Similar results were obtained by IHC. Consistent with mRNA changes, ESR1 regulated miRNA such as miR-107 (P=0.007) and miRNA important in tamoxifen resistance such as mir-451 (P= 0.0003) were also altered in MV165-NR group compared to vehicle. Conclusion: These results suggest that treatment with BEV may alter the intrinsic subtypes in the presence of VEGF expression. These data may help to explain the variable results to anti-VEGF therapy based on the duration of BEV treatment.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-04-02.

Management of primary and metastatic triple negative breast cancer: perceptions of oncologists from India

BACKGROUND

In order to document the understanding of current evidence for the management of triple negative breast cancer and application of this knowledge in daily practice, we conducted an interactive survey of practicing Indian oncologists.

MATERIALS AND METHODS

A core group of academic oncologists devised two hypothetical triple negative cases (metastatic and early breast cancer, respectively) and multiple choice options under different clinical circumstances. The respondents were practicing oncologists in different Indian cities who participated in either an online survey or a meeting. The participants electronically chose their preferred option based on their everyday practice.

RESULTS

A total of 152 oncologists participated. Just over half (53.8%) preferred taxane based chemotherapy as first-line chemotherapy in the metastatic setting. In the adjuvant setting, a taxane regimen was chosen by 61%. Over half of respondents (52.6%) underestimated the baseline survival of a patient with node positive triple-negative tumor and 18.9% overestimated this survival compared to the estimate of the Adjuvant! program.

DISCUSSION

This data offers insight into the perceptions and practice of a diverse cross-section of practicing oncologists in India with respect to their therapeutic choices in metastatic and adjuvant settings in triple negative breast cancer.

TRPV1 expression-dependent initiation and regulation of filopodia

Transient receptor potential vanilloid subtype 1 (TRPV1), a non-selective cation channel, is present endogenously in dorsal root ganglia (DRG) neurons. It is involved in the recognition of various pain producing physical and chemical stimuli. In this work, we demonstrate that expression of TRPV1 induces neurite-like structures and filopodia and that the expressed protein is localized at the filopodial tips. Exogenous expression of TRPV1 induces filopodia both in DRG neuron-derived F11 cells and in non-neuronal cells, such as HeLa and human embryonic kidney (HEK) cells. We find that some of the TRPV1 expression-induced filopodia contain microtubules and microtubule-associated components, and establish cell-to-cell extensions. Using live cell microscopy, we demonstrate that the filopodia are responsive to TRPV1-specific ligands. But both, initiation and subsequent cell-to-cell extension formation, is independent of TRPV1 channel activity. The N-terminal intracellular domain of TRPV1 is sufficient for filopodial structure initiation while the C-terminal cytoplasmic domain is involved in the stabilization of microtubules within these structures. In addition, exogenous expression of TRPV1 results in altered cellular distribution and in enhanced endogenous expression of non-conventional myosin motors, namely myosin IIA and myosin IIIA. These data indicate a novel role of TRPV1 in the regulation of cellular morphology and cellular contact formation.

TRPV1 at nerve endings regulates growth cone morphology and movement through cytoskeleton reorganization

While the importance of Ca(2+) channel activity in axonal path finding is established, the underlying mechanisms are not clear. Here, we show that transient receptor potential vanilloid receptor 1 (TRPV1), a member of the TRP superfamily of nonspecific ion channels, is physically and functionally present at dynamic neuronal extensions, including growth cones. These nonselective cation channels sense exogenous ligands, such as resenifera toxin, and endogenous ligands, such as N-arachidonoyl-dopamine (NADA), and affect the integrity of microtubule cytoskeleton. Using TRPV1-transiently transfected F11 cells and embryonic dorsal root ganglia explants, we show that activation of TRPV1 results in growth cone retraction, and collapse and formation of varicosities along neurites. These changes were due to TRPV1-activation-mediated disassembly of microtubules and are partly Ca(2+)-independent. Prolonged activation with very low doses (1 nM) of NADA results in shortening of neurites in the majority of isolectin B4-positive dorsal root ganglia neurones. We postulate that TRPV1 activation plays an inhibitory role in sensory neuronal extension and motility by regulating the disassembly of microtubules. This might have a role in the chronification of pain.

Identification and characterisation of novel tubulin-binding motifs located within the C-terminus of TRPV1

Previously, we reported that TRPV1, the vanilloid receptor, interacts with soluble alphabeta-tubulin dimers as well as microtubules via its C-terminal cytoplasmic domain. The interacting region of TRPV1, however, has not been defined. We found that the TRPV1 C-terminus preferably interacts with beta-tubulin and less with alpha-tubulin. Using a systematic deletion approach and biotinylated-peptides we identified two tubulin-binding sites present in TRPV1. These two sequence stretches are highly conserved in all known mammalian TRPV1 orthologues and partially conserved in some of the TRPV1 homologues. As these sequence stretches are not similar to any known tubulin-binding sequences, we conclude that TRPV1 interacts with tubulin and microtubule through two novel tubulin-binding motifs.

Rapid disassembly of dynamic microtubules upon activation of the capsaicin receptor TRPV1

The transmission of pain signalling involves the cytoskeleton, but mechanistically this is poorly understood. We recently demonstrated that the capsaicin receptor TRPV1, a non-selective cation channel expressed by nociceptors that is capable of detecting multiple pain-producing stimuli, directly interacts with the tubulin cytoskeleton. We hypothesized that the tubulin cytoskeleton is a downstream effector of TRPV1 activation. Here we show that activation of TRPV1 results in the rapid disassembly of microtubules, but not of the actin or neurofilament cytoskeletons. TRPV1 activation mainly affects dynamic microtubules that contain tyrosinated tubulins, whereas stable microtubules are apparently unaffected. The C-terminal fragment of TRPV1 exerts a stabilizing effect on microtubules when over-expressed in F11 cells. These findings suggest that TRPV1 activation may contribute to cytoskeleton remodelling and so influence nociception.

Identification and characterization of a Ca2+ -sensitive interaction of the vanilloid receptor TRPV1 with tubulin

The vanilloid receptor TRPV1 plays a well-established functional role in the detection of a range of chemical and thermal noxious stimuli, such as those associated with tissue inflammation and the resulting pain. TRPV1 activation results in membrane depolarization, but may also trigger intracellular Ca2+ -signalling events. In a proteomic screen for proteins associated with the C-terminal sequence of TRPV1, we identified beta-tubulin as a specific TRPV1-interacting protein. We demonstrate that the TRPV1 C-terminal tail is capable of binding tubulin dimers, as well as of binding polymerized microtubules. The interaction is Ca2+ -sensitive, and affects microtubule properties, such as microtubule sensitivity towards low temperatures and nocodazole. Our data thus provide compelling evidence for the interaction of TRPV1 with the cytoskeleton. The Ca2+ -sensitivity of this interaction suggests that the microtubule cytoskeleton at the cell membrane may be a downstream effector of TRPV1 activation.

Molecular and functional characteristics, growth promoting effect and persistence of selected parent isolates and streptomycin resistant derivatives of rice rhizobacteria

Molecular and functional characteristics of seven azospirilla and five phosphorus solubilizing bacteria (PSB) isolates of rice rhizosphere, growth promotion ability of two efficient strains, Azospirillum amazonense A10 (MTCC4716) and Bacillus megaterium P5 (MTCC4714) and their persistence based on streptomycin resistant derivatives (SRD), were determined. SDS-PAGE and isozyme banding patterns of the isolates were used to arbitrarily group the azospirilla into 4 and PSB into 3 clusters and as markers to ascertain their identity. The azospirilla produced 2.0 to 10.5 ppm of IAA like substances and showed nitrogenase activity of 0.02 to 3.55 nmole C2H4/hr/ml of pure culture. PSB isolates produced 7.8 to 15.0 ppm IAA like substances and 20 to 128 ppm soluble P. Induction of resistance to streptomycin resulted in changes of these properties. Co-inoculation of rice with SRD A10 and SRD P5 and their parental strains in separate treatments enhanced grain yield over control by 31 and 12.4%, respectively. Nitrogenase activity of rice roots under SRD co-inoculated treatment was higher (4.16 nmole C2H4/hr/hill) than that-under parental strains co-inoculated treatment (3.76 nmole C2H4/hr/hill). SDS-PAGE profile and population count of the strains confirmed their establishment in rice rhizosphere and persistence over a year after inoculation.

Hodgkin's disease relapse presenting as Pancoast's syndrome

Among the various infrequent causes of Pancoast's syndrome, Hodgkin's disease is one. A 26 year old man was diagnosed as Hodgkin's disease. Five years later the disease relapsed producing Pancoast's syndrome. The importance of precise aetiological diagnosis before treatment of such cases with similar presentation is emphasized.