Effect of heavy metals on microbial biomass and activities in century old landfill soil

A study was conducted to determine the effect of metals on soil microbial biomass and activities in landfill soils as well as normal background soil. The microbial biomass and activities were consistently higher in the landfill soils than in the background soil. Significant positive correlations existed between the microbial parameters and soil organic carbon. The landfill soils contained higher concentrations of metals (iron, manganese, copper, cadmium, lead and zinc) than did the background soil. Microbial parameters were negatively correlated with the metals, with inhibition increasing with the bioavailability of the metals. It is suggested that the metals affected microbial biomass and activities by behaving synergistically or additively with each other. Although the landfill soils had higher microbial biomass and activities than the background soil, due to higher organic matter content, the ratios of microbial parameters/organic carbon indicated that inhibition of microbial growth and activities had occurred due to metal stress.

Characterization of frequency noise on a broadband infrared frequency comb using optical heterodyne techniques

We measure the frequency noise across a Cr:forsterite infrared frequency comb through the optical heterodyne beat of different comb teeth against stable continuous wave (CW) lasers. This sensitive measurement shows strong correlations of the frequency noise between spectral components of the comb, relative to a fixed optical frequency near the 1.3 micron carrier of the Cr:forsterite laser. The correlated frequency fluctuations are shown to arise from amplitude noise on the pump laser. We also report a preliminary comparison of excess noise that occurs during supercontinuum generation in both highly nonlinear fiber and an extruded glass microstructured fiber.

Development of a real-time PCR-based method for rapid differential identification of Mycobacterium species

AIMS

To develop a real-time PCR method for rapid differential identification of many clinically important mycobacteria to the species level.

METHODS AND RESULTS

Eighteen Mycobacterium species that are considered clinically important were targeted for the identification. One primer pair and 21 pairs of hybridization probes (HybProbes) specific for the genus, species or complex were designed based on the rpoB gene sequences of mycobacteria. Twenty-five different Mycobacterium reference species were tested. In a single round of real-time PCR, all the nontuberculous mycobacteria (NTM) species tested were identified at the genus level and 16 of the 18 targeted species were differentially identified to the species or complex level during the amplification cycles; subsequent melting curve analysis allowed the specific identification of all the target species at the species or complex level without cross-reactivity with the other species.

CONCLUSIONS

The developed real-time PCR assay rapidly identifies the NTM at the genus level and 18 clinically important Mycobacterium species at the species or complex level.

SIGNIFICANCE AND IMPACT OF THE STUDY

This real-time PCR assay provides a useful tool for the rapid differentiation of most clinically important Mycobacterium species.

Molecular and functional expression of anion exchangers in cultured normal human nasal epithelial cells

Aims

Anions have an important role in the regulation of airway surface liquid (ASL) volume, viscosity and pH. However, functional localization and regulation of anion exchangers (AEs) have not been clearly described. The aim of this study was to investigate the regulation of AE mRNA expression level in accordance with mucociliary differentiation and the functional expression of AEs cultured normal human nasal epithelial (NHNE) cells.

Methods

Nasal mucosal specimens from three patients are obtained and serially cultured cells are subjected to morphological examinations, RT-PCR, Western blot analysis and immunocytochemistry. AE activity is assessed by pHi measurements.

Results

Expression of ciliated cells on the apical membrane and expression of MUC5AC, a marker of mucous differentiation, increased with time. AE2 and SLC26A4 mRNA expression decreased as mucociliary differentiation progressed, and AE4, SLC26A7 and SLC26A8 mRNA expression increased on the 14th and 28th day after confluence. Accordingly, AE4 protein expression also progressively increased. AE activity in 100 mm K⁺ buffer solutions was nearly twofold higher than that in 5 mm K⁺ buffer solutions. Moreover, only luminal AE activity increased about fourfold over the control in the presence of 5 μm forskolin. In the presence of 100 μm adenosine-5′-triphosphate (ATP) which evokes intracellular calcium signalling through activation of purinergic receptors, only luminal AE activity was again significantly increased. On the other hand, 500 μm 4,4′-diisothiocyanostilbene-2,2′-disulfonic acid (DIDS), an inhibitor of most SLC4 and SLC26AE isoforms, nearly abolished AE activity in both luminal and basolateral membranes. We found that AE activity was affected by intracellular cAMP and calcium signalling in the luminal membrane and was DIDS-sensitive in both membranes of cultured NHNE cells.

Conclusion

Our findings through molecular and functional studies using cultured NHNE cells suggest that AEs may have an important role in the regulation of ASL.

Multikilohertz optical parametric chirped pulse amplification in periodically poled stoichiometric LiTaO3 at 1235 nm

We demonstrate, for the first time to our knowledge, multikilohertz operation of a double-stage optical parametric chirped pulse amplifier with periodically poled stoichiometric LiTaO3 crystals, seeded by a homemade Cr:forsterite oscillator operating at 1235 nm. The repetition rate of the amplifier could easily be tuned without the use of electro-optic modulators by using a repetition-rate-tunable kilohertz pump laser operating at 532 nm and a time-synchronization unit. Amplified total (signal+idler) energies of 55.9 and 36.2 microJ were achieved at 1 and 5 kHz, respectively. After recompression, the pulse width of amplified idler pulses at 1235 nm amounted to 530 fs.

Measurement of ocular torsion using digital fundus image

Computer-based objective measurement of the ocular cyclotorsion using digital fundus photograph was developed. Color digital fundus photographs acquired with the field angle of 60 degrees , 1520 x 1080 in resolution were analyzed. Optic disc and macula were segmented by the program developed on MATLAB, which executed the serial analysis of the Otsu threshold, labeling, Canny edge. The angle between the horizontal line that bisects the optic disc and the line connecting the center of optic disc and macula was measured and compared with the torsion determined by the specialist. Optic disc and macula were segmented and the mean of the calculated angle was 3.02+/-1.24 degrees . The mean of the torsion determined by the specialist was 3.13+/-1.98 degrees and there was no difference between the two. The measurement of the cyclotorsion using computer program showed good coincidence with that of the specialist and it can be a good candidate as a tool helping precise diagnosis and the objective evaluation of the disease for the physicians.

FMRFamide-like neuropeptides and mechanosensory touch receptor neurons regulate male sexual turning behavior in Caenorhabditis elegans

Caenorhabditis elegans male mating provides a powerful model to study the relationship between the nervous system, genes, and innate sexual behaviors. Male mating is the most complex behavior exhibited by the nematode C. elegans and involves the steps of response, backing, turning, vulva location, spicule insertion, and sperm transfer. Because neuropeptides are important neural regulators of many complex animal behaviors, we explored the function of the FMRFamide-like neuropeptide (flp) gene family in regulating male copulation. We found that peptidergic signaling mediated by FMRF-amide like neuropeptides (FLPs) FLP-8, FLP-10, FLP-12, and FLP-20 is required for the sensory transduction involved in male turning behavior. flp-8, flp-10, flp-12, and flp-20 mutant males significantly increase repetition of substep(s) of turning behavior compared with wild-type males. Genes controlling neuropeptide processing and secretion in general, including egl-3, egl-21, ida-1, and unc-31, are also required for inhibiting repetitive turning behavior. Neuropeptidergic signaling adjusts the repetitiveness of turning independently of serotonergic modulation of the timing of turning. Surprisingly, the mechanosensitive touch receptor neurons are found to be part of the neural circuitry regulating male turning behavior, indicating the existence of functional dimorphisms in the nervous system with regard to sex-specific behaviors.

A single institutional experience of thymic epithelial tumours over 11 years: clinical features and outcome and implications for future management

Thymic epithelial tumours (TETs), the most common tumour of the anterior mediastinum, are epithelial neoplasms of the thymus with a wide spectrum of morphologic features. We retrospectively analysed clinical features of TET and the correlation of World Health Organisation (WHO) histologic classification and Masaoka staging system with different treatment modalities in 195 patients, from 1995 to 2005. According to the Masaoka's staging system, there were 78 (40.0 %) patients with stage I, 38 (19.5%) with stage II, 41 (21.0%) with stage III, 38 (19.5%) with stage IV. All patients were reclassified according to the WHO criteria as follows: Type A (n=9, 4.6%), AB (n=37, 18.9%), B1 (n=29, 14.8%), B2 (n=48, 24.6%), B3 (n=40, 20.5%), C (n=32, 16.4%). There was a fairly good correlation between Masaoka staging and WHO histotype (P<0.05). However, in multivariate analysis, the tumour stage and WHO histotype were two independent factors separately for predicting overall survival (P<0.001, P<0.001, respectively). Thus, both Masaoka stage and WHO histotype should be considered in risk stratification of therapy for TET patients. Patients with completely resected types B2, B3 and C and adjuvant radiotherapy (n=57) had more favourable disease-free and overall survival as compared with those without adjuvant treatment (n=20) (P=0.015, 0.015, respectively). Given that the predominant sites of recurrence after surgery was pleura/pericardium and lung, and the fact that complete resection was a significant influential factor for survival at log–rank test, an active investigation of newer treatment strategies such as neoadjuvant treatment to improve the resectability and development of optimal adjuvant treatment modality is a high priority especially for those with high-risk for recurrence or in patients with advanced stage disease.

The RNAi pathway initiated by Dicer-2 in Drosophila

Injection or expression of double-stranded RNA (dsRNA) in Drosophila serves as a trigger that causes cells to specifically cleave homologous mRNA transcripts. Our approach is to identify essential components of the RNA interference (RNAi) mechanism by isolating and characterizing mutations that cause the RNAi response to be abnormal. These studies have thus far led to the identification of seven genetic loci that encode proteins acting at various steps in the RNAi process. We have molecularly identified several of these proteins. Two are members of the Dicer family. Dicer-1 and Dicer-2 are required for short interfering RNA (siRNA)-directed mRNA cleavage by facilitating distinct steps in the assembly of the RNA-induced silencing complex (RISC). AGO2 is a RISC component that both carries out transcript cleavage and facilitates RISC maturation. Other factors appear to function as regulators of RISC assembly rather than as core factors for RNAi.

Preliminary results from a phase I/II study of the combination of lenalidomide and DTIC in patients with metastatic malignant melanoma previously untreated with systemic chemotherapy

8533

Background: In metastatic melanoma (MM) no single agent has shown objective response greater than 21%, and none have made an impact on overall survival. DTIC is approved for MM with response rates of 7% to 21%. Lenalidomide, an immunomodulatory drug of the IMiDs class, was reported to enhance immune responses in MM patients. This study was designed to assess the safety and activity of lenalidomide in combination with DTIC in patients with metastatic melanoma (MM). Methods: Twenty-eight chemotherapy naive patients with unresectable stage III and IV MM enrolled in the study. All patients received 25 mg lenalidomide orally once daily on days 1–14 every 21 days and continued therapy as tolerated or until disease progression. DTIC was given IV over 1 hour on day 1 every 21 days. There were three dose levels for DTIC: 600 mg/m2, 800 mg/m2 and 1,000 mg/m2. Each dose level had 3–6 patients enrolled. Thirteen additional patients were to be enrolled at the MTD. Response and progression were evaluated using the RECIST criteria every 6 weeks. Results: As of December 21, 2006 twenty-six patients were evaluable for response. Median age was 65 (46–83) and 13 were female. Median ECOG was 1. Two patients (8%) exhibited an objective response (2 partial responses (PR)), 10 had stable disease (SD) for a tumor control rate (TCR) of 46 % and 14 progressive disease (PD). Thirteen patients have been enrolled at the MTD of 25 mg lenalidomide + 800 mg/m2 DTIC and most are still receiving therapy. Grade 3 or 4 adverse events occurred in 12 (43%) of the 28 patients receiving drug. Grade 3 events included: transient elevation of transaminases, increased temperature, headache, dizziness, low hemoglobin, and leg edema. Four patients (14%) experienced a Grade 4 adverse reaction (pulmonary emboli, low hemoglobin, cerebral hemorrhage, and cerebral ischemia). The most common Grade 1/2 adverse events included: fatigue, nausea, pruritis, muscle cramps, taste alteration, skin rash, and constipation. Conclusions: The MTD has been established at 25 mg lenalidomide + 800 mg/m2 DTIC. Preliminary results indicate that lenalidomide in combination with DTIC has manageable side effects in patients with MM. Evaluation of efficacy is ongoing.

No significant financial relationships to disclose.