TRPP2 and TRPV4 form an EGF-activated calcium permeable channel at the apical membrane of renal collecting duct cells

Objective

Regulation of apical calcium entry is important for the function of principal cells of the collecting duct. However, the molecular identity and the regulators of the transporter/channel, which is responsible for apical calcium entry and what factors regulate the calcium conduction remain unclear.

Methods and Results

We report that endogenous TRPP2 and TRPV4 assemble to form a 23-pS divalent cation-permeable non-selective ion channel at the apical membrane of renal principal cells of the collecting duct. TRPP2\TRPV4 channel complex was identified by patch-clamp, immunofluorescence and co-immunprecipitation studies in both principal cells that either possess normal cilia (cilia (+)) or in which cilia are absent (cilia (-)). This channel has distinct biophysical and pharmacological and regulatory profiles compared to either TRPP2 or TRPV4 channels. The rate of occurrence detected by patch clamp was higher in cilia (-) compared to cilia (+) cells. In addition, shRNA knockdown of TRPP2 increased the prevalence of TRPV4 channel activity while knockdown of TRPV4 resulted in TRPP2 activity and knockdown of both proteins vastly decreased the 23-pS channel activity. Epidermal growth factor (EGF) stimulated TRPP2\TRPV4 channel through the EGF receptor (EGFR) tyrosine kinase-dependent signaling. With loss of cilia, apical EGF treatment resulted in 64-fold increase in channel activity in cilia (-) but not cilia (+) cells. In addition EGF increased cell proliferation in cilia (-) cell that was dependent upon TRPP2\TRPV4 channel mediated increase in intracellular calcium.

Conclusion

We conclude that in the absence of cilia, an EGF activated TRPP2\TRPV4 channel may play an important role in increased cell proliferation and cystogenesis.

Effects of Rhynchophylline on relaxation and contraction of the bladder detrusor in rats

AIM

The aim of this study was to observe the effects of Rhynchophylline (Rhy) on the relaxation and contraction of rat bladder detrusor and urodynamics and determine the changes in the tension of isolated rat bladder muscle strips.

MATERIALS AND METHODS

Rats were randomly divided into four groups: sham-operated, overactive bladder (OAB) model, Rhy-treated, and the control group. Sections of urodynamic testing and electrophysiological OAB indicators of detrusor were measured. The effect of tension on the isolated rat bladder detrusor muscle strips was determined; activators and antagonists of calcium-activated potassium ion channels were detected in vitro using the tension method. The contraction of detrusor muscle strips and the antagonism of acetylcholine due to changes in muscle contraction were observed.

RESULTS

The Rhy-treated group significantly decreased the maximum bladder capacity, bladder filling pressure, leak point pressure, contraction frequency, motility index (p < 0.05). The affinity index of Rhy was 4.53 ± 0.22. However, 1 µmol/L to 2 μmol/L Rhy shifts CaCl2 cumulative dose-response curves to the right in a non-parallel manner, showing a non-competitive antagonism. Rhy inhibits detrusor contraction by blocking L-type calcium channels and activating big-conductance calcium-activated potassium channels. A low concentration of Rhy can inhibit muscle contraction caused by intracellular calcium.

CONCLUSIONS

Rhy plays an important role in OAB treatment and decreases effectively on sections of urodynamic testing and electrophysiological OAB indicators of detrusor.

Investigating hydrophobic ligand-receptor interactions in parathyroid hormone receptor using peptide probes

With an increasing number of new chemical entities entering clinical studies, and an increasing share of the market, peptides and peptidomimetics constitute one of the most promising classes of therapeutics. The success of synthetic peptides as therapeutics relies on the lead optimization step in which the lead candidates are modified to improve drug-like properties of peptides related to potency, pharmacokinetics, solubility, and stability, among others. Peptidomimetics based on the N-terminal stretch of the first 11 amino acids of the PTH have been investigated as potential lead compounds for the treatment of osteoporosis. On the basis of a peptide reported in the literature, referred to here as the Parent Peptide (H-Aib-Val-Aib-Glu-Ile-Gln-Leu-Nle-His-Gln-Har-NH2), we conducted systematic SAR analyses to investigate the effects of altering peptide hydrophobicity on PTH receptor functional potency as measured by the cAMP (cyclic adenosine monophosphate) accumulation and β-arrestin recruitment assays. Among hydrophobic residues, we found that the Val2 position shows the least flexibility in terms of the SAR studies, whereas the Leu7 position appeared to be most flexible. Through circular dichroism and nuclear magnetic resonance spectroscopy studies, we were able to establish that changes in hydrophobic residues significantly change the extent of peptide helicity and that the helical character correlates well with receptor agonist activity. Here, we report several novel PTH 1-11 peptidomimetics that show comparable or enhanced potency to stimulate Gs-signaling over β-arrestin recruitment as compared with such properties of PTH 1-34 and the Parent Peptide.

ER stress signalling through eIF2α and CHOP, but not IRE1α, attenuates adipogenesis in mice

AIMS/HYPOTHESIS

Although obesity is associated with endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) in adipose tissue, it is not known how UPR signalling affects adipogenesis. To test whether signalling through protein kinase RNA-like ER kinase/eukaryotic initiation factor 2 alpha (PERK/eIF2α) or inositol-requiring enzyme 1 alpha/X-box binding protein 1 (IRE1α/XBP1) is required for adipogenesis, we studied the role of UPR signalling in adipocyte differentiation in vitro and in vivo in mice.

METHODS

The role of UPR signalling in adipogenesis was investigated using 3T3-L1 cells and primary mouse embryonic fibroblasts (MEFs) by activation or inhibition of PERK-mediated phosphorylation of the eIF2α- and IRE1α-mediated splicing of Xbp1 mRNA. Body weight change, fat mass composition and adipocyte number and size were measured in wild-type and genetically engineered mice fed a control or high-fat diet (HFD).

RESULTS

ER stress repressed adipocyte differentiation in 3T3-L1 cells. Impaired eIF2α phosphorylation enhanced adipocyte differentiation in MEFs, as well as in mice. In contrast, increased eIF2α phosphorylation reduced adipocyte differentiation in 3T3-L1 cells. Forced production of CCAAT/enhancer binding protein (C/EBP) homologous protein (CHOP), a downstream target of eIF2α phosphorylation, inhibited adipogenesis in 3T3-L1 cells. Mice with deletion of Chop (also known as Ddit3) (Chop (-/-)) gained more fat mass than wild-type mice on HFD. In addition, Chop deletion in genetically obese Lepr (db/db) mice increased body fat mass without altering adipocyte size. In contrast to the eIF2α-CHOP pathway, activation or deletion of Ire1a (also known as Ern1) did not alter adipocyte differentiation in 3T3-L1 cells.

CONCLUSIONS/INTERPRETATION

These results demonstrate that eIF2α-CHOP suppresses adipogenesis and limits expansion of fat mass in vivo in mice, rendering this pathway a potential therapeutic target.

A platform to parallelize planar surfaces and control their spatial separation with nanometer resolution

Parallelizing planar surfaces and manipulating them into close proximity with spatial separation of nanoscale dimensions is critical for probing phenomena such as near-field radiative heat transport and Casimir forces. Here, we report on a novel platform, with an integrated reflected light microscope, that is capable of parallelizing two planar surfaces such that the angular deviation is <6 μrad, while simultaneously allowing control of the gap from 15 μm down to contact with ∼0.15 nm resolution. The capabilities of this platform were verified by using two custom-fabricated micro-devices with planar surfaces, 60 × 60 μm(2) each, whose flatness and surface roughness were experimentally quantified. We first parallelized the two micro-devices by using the developed platform in conjunction with a simple optical approach that relies on the shallow depth of field (∼2 μm) of a long working distance microscope objective. Subsequently, we experimentally tested the parallelism achieved via the optical alignment procedure by taking advantage of electrodes integrated into the micro-devices. Our measurements unambiguously show that the simple depth-of-field based optical approach enables parallelization such that the angular deviation between the two surfaces is within ∼500 μrad. This ensures that the separation between any two corresponding points on the parallel surfaces deviate by ∼30 nm or less from the expected value. Further, we show that improved parallelization can be achieved using the integrated micro-electrodes which enable surface roughness limited parallelization with deviations of ∼5 nm from parallelism.

Gate dependent photo-responses of carbon nanotube field effect phototransistors

Gate dependent photoconductivity of carbon nanotube (CNT) field effect phototransistors (FEPs) was systematically investigated in this study. The photo-response comparisons of CNT FEPs with symmetric and asymmetric metal structures connecting to the same CNT revealed that the gate effect contributed to a sensitivity improvement with a lower dark current, a higher photocurrent, and an enhanced photovoltage. A functionalized asymmetric FEP, fabricated by partially doping the CNT utilizing a polyethylene imine (PEI) polymer, verified that FEPs delivered a better performance by using asymmetric structures. A multi-gate FEP, with three pairs of side-gates that can electrostatically dope different sections of a CNT independently, was fabricated to examine the gate structure dependent photo-responses. Experimental measurements showed an unconventional photocurrent improvement that was weakly dependent on the gate location, which was attributed to the unique charge distribution of one-dimensional semiconductors.

Differential contribution of TM6 and TM12 to the pore of CFTR identified by three sulfonylurea-based blockers

Previous studies suggested that four transmembrane domains 5, 6, 11, 12 make the greatest contribution to forming the pore of the CFTR chloride channel. We used excised, inside-out patches from oocytes expressing CFTR with alanine-scanning mutagenesis in amino acids in TM6 and TM12 to probe CFTR pore structure with four blockers: glibenclamide (Glyb), glipizide (Glip), tolbutamide (Tolb), and Meglitinide. Glyb and Glip blocked wildtype (WT)-CFTR in a voltage-, time-, and concentration-dependent manner. At V (M) = -120 mV with symmetrical 150 mM Cl(-) solution, fractional block of WT-CFTR by 50 μM Glyb and 200 μM Glip was 0.64 ± 0.03 (n = 7) and 0.48 ± 0.02 (n = 7), respectively. The major effects on block by Glyb and Glip were found with mutations at F337, S341, I344, M348, and V350 of TM6. Under similar conditions, fractional block of WT-CFTR by 300 μM Tolb was 0.40 ± 0.04. Unlike Glyb, Glip, and Meglitinide, block by Tolb lacked time-dependence (n = 7). We then tested the effects of alanine mutations in TM12 on block by Glyb and Glip; the major effects were found at N1138, T1142, V1147, N1148, S1149, S1150, I1151, and D1152. From these experiments, we infer that amino acids F337, S341, I344, M348, and V350 of TM6 face the pore when the channel is in the open state, while the amino acids of TM12 make less important contributions to pore function. These data also suggest that the region between F337 and S341 forms the narrow part of the CFTR pore.

Possible function of the frenulum of prepuce in penile erection

Fremulum of prepuce was the ruffle of foreskin while there was little about the function of fremulum. This study discusses the possible function of the frenulum of prepuce in penile erection. Twelve patients had premature ejaculation (PE) whose frenula were short. Two patients suffered unsatisfied intercourse whose frenula were damaged and departed 12 or 6 months earlier. We prolonged the short frenulum and reconstructed the ruptured frenulum. All patients reported satisfied sexual intercourse after 3-6 months. It is concluded that the frenulum is important in penile erection. PE might be treated by lengthening the frenulum.

Effect of exogenous l-arginine and ageing on NO and ET-1 in penile tissue of rat

The aim of this study was to investigate the effect and significance of l-arginine and ageing on nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) pathway and ET-1 in penile tissue of rats. The different months old rats were divided into control group and experiment group randomly, the content of NO, cGMP, the changes of activity of Nitrous Oxide Systems (NOS) and the content of endothelin-1(ET-1) in penile tissue were determined. Along with ageing, NO and the activity of NOS in penile tissue increased at first and then decreased (P < 0.001). The content of cGMP reduced obviously (P < 0.001), the content of ET-1 had a tendency to increase, and the ratio of ET-1/NO increased significantly (P < 0.001 or P < 0.01). After feeding rats with l-arginine for some time, both the activity of NOS and the content of cGMP increased significantly in penile tissue (P < 0.001), while there was no obvious change in the content of ET-1. Our study shows that whether the smooth muscle cells relax or contract might be decided by the content of cGMP and value of ET-1/NO in penile tissue. l-arginine had significant effect on increasing the activity of NOS and the content of NO and cGMP, indicating that l-arginine has potential clinical value to be used in treating ED.

Cathepsin L is associated with proliferation and clinical outcome of urothelial carcinoma of the bladder

Increasing evidence suggests that the activity of cysteine proteases, including cathepsin L, is important in cancer cell invasion and metastasis. This study was designed to investigate the clinicopathological and prognostic significance of cathepsin L in human urothelial carcinoma of the bladder (UCB). Standard immunohistochemistry was used to determine the presence of cathepsin L and Ki-67 (a marker of proliferation) in paraffin-embedded specimens of 82 human UCB cases. Cathepsin L protein was localized in the cytoplasm of the malignant UCB cells, and was significantly associated with the pathological tumour stage (invasiveness), tumour grade, survival, local tumour recurrence during follow-up, the occurrence of distant metastasis during follow-up and the presence of Ki-67 protein. Multivariate analysis using the Cox proportional hazards model revealed that cathepsin L immunopositivity and pathological tumour stage (invasiveness) were independent significant prognostic factors for overall survival. This study showed that cathepsin L provides significant prognostic information and that it might be a useful therapeutic target in the future.

Dynamics of population communities with prey migrations and Allee effects: a bifurcation approach

The population dynamics of predator-prey systems in the presence of patch-specific predators are explored in a setting where the prey population has access to both habitats. The emphasis is in situations where patch-prey abundance drives prey dispersal between patches, with the fragile prey populations, i.e. populations subject to the Allee effect. The resulting 3D and 4D non-linear systems depending on some parameters, which reflect 'measures' of factors under consideration, support rich dynamics and in particular a diverse number of predator-prey life history outcomes. The model's mathematical analysis is carried out via submodels that focus in lower-dimensional settings. The outcomes depend on and, in fact, are quite sensitive to the structure of the system, the range of parameter values and initial conditions. We show that the system can support multistability and a diverse set of predator-prey life-history dynamics that include rather complex dynamical system outcomes. It is argued that, in general, evolution should favour heterogeneous settings including Allee effects, prey refuges and patch-specific predators.

High strain rate testing of bovine trabecular bone

In spinal vertebral burst fractures, the dynamic properties of the trabecular centrum, which is the central region of porous bone inside the vertebra, can play an important role in determining the failure mode. If the failure occurs in the posterior portion of the vertebral body, spinal canal occlusion can occur and ejected trabecular bone can impact the spinal cord resulting in serious injury. About 15% of all spinal cord injuries are caused by such burst fractures. Unfortunately, due to the uniqueness of burst fracture injuries, postinjury investigation cannot always accurately assess the degree of damage caused by these fractures. This research makes an effort to begin understanding the governing effects in this important bone fracture event. Measurements of the dynamic deformation response of bovine trabecular bone with the marrow intact and marrow removed using a modified split-Hopkinson pressure bar apparatus are reported and compared with quasistatic deformation response results. Because trabecular bone is more compliant and lower in strength than cortical bone, typical Hopkinson pressure bar experimental techniques used for high strain rate testing of harder materials cannot be applied. Instead, a quartz-crystal-embedded, split-Hopkinson pressure bar developed for testing compliant, low strength materials is used. Care is taken into account for the orthotropic properties in the bone by testing only along the principle material axes, determined through microcomputed tomography. In addition, shaping of the stress wave pulse is used to ensure a constant strain rate and homogeneous specimen deformation. Results indicate that the strength of trabecular bone increases by a factor of approximately 2-3 when the strain rate increases from 10(-3) s(-1) to 500 s(-1) and that the bone fractures beyond a critical strain.

The unfolded protein response is required to maintain the integrity of the endoplasmic reticulum, prevent oxidative stress and preserve differentiation in β-cells

Diabetes is an epidemic of worldwide proportions caused by β-cell failure. Nutrient fluctuations and insulin resistance drive β-cells to synthesize insulin beyond their capacity for protein folding and secretion and thereby activate the unfolded protein response (UPR), an adaptive signalling pathway to promote cell survival upon accumulation of unfolded protein in the endoplasmic reticulum (ER). Protein kinase-like endoplasmic reticulum kinase (PERK) signals one component of the UPR through phosphorylation of eukaryotic initiation factor 2 on the α-subunit (eIF2α) to attenuate protein synthesis, thereby reducing the biosynthetic burden. β-Cells uniquely require PERK-mediated phosphorylation of eIF2α to preserve cell function. Unabated protein synthesis in β-cells is sufficient to initiate a cascade of events, including oxidative stress, that are characteristic of β-cell failure observed in type 2 diabetes. In contrast to acute adaptive UPR activation, chronic activation increases expression of the proapoptotic transcription factor CAAT/enhancer-binding protein homologous protein (CHOP). Chop deletion in insulin-resistant mice profoundly increases β-cell mass and prevents β-cell failure to forestall the progression of diabetes. The findings suggest an unprecedented link by which protein synthesis and/or misfolding in the ER causes oxidative stress and should encourage the development of novel strategies to treat diabetes.

Optimization of selected cultivation parameters for Cordyceps guangdongensis

AIMS

To increase the fruit body production of Cordyceps guangdongensis, selected cultivation conditions, especially nutritional parameters were optimized.

METHODS AND RESULTS

Cordyceps guangdongensis was inoculated on potato dextrose agar slants with pH values from 4.5 to 9.0 and cultivated in artificial media with different carbon and nitrogen supplements. Primordium formation in C. guangdongensis was favoured by slightly acidic conditions. Fruit body yields and biological efficiency (BE) recorded were all highest in cultures of C. guangdongensis supplemented with sucrose and KNO3 as carbon and nitrogen supplements, respectively. Highest fruit body yields and BE values were recorded with C : N ratio of 12 : 1. The optimal medium consisted of (g l(-1)) 20.0 sucrose, 4.0 soya bean powder, 5.0 beef extract and 10.0 KNO3. Cultivation experiments using this medium confirmed its reliability; 18.35% of BE was obtained, compared with a calculated maximum BE of 18.65% based on orthogonal test data.

CONCLUSIONS

Cordyceps guangdongensis preferred sucrose and potassium nitrate as best carbon and nitrogen supplements. It produced satisfying yield of fruit body with optimized medium.

SIGNIFICANCE AND IMPACT OF THE STUDY

Optimized artificial cultivation conditions could promote the yield of C. guangdongensis and decreased the cost of production.

One-step route to wurtzite-structured ZnS thin nanorods in pure ethylenediamine or mixed solvent

In the paper, we report one-step synthesis of novel wurtzite-structured ZnS three dimensional architectures assembled from thin nanorods in mixed solvent of ethylenediamine (en) and ethylene glycol, and wurtzite ZnS nanorods in a pure en solvent, both adopting Zn(CH3COO)2 x 2H2O and (NH2)2CS as raw materials. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy and selected area electron diffraction were applied to characterize the samples. It was found that the volume ratio of solvents and the concentration of (NH2)2CS played important roles in the formation of wurtzite-structured ZnS nanorods, and the thin wurtzite ZnS nanorods with mean diameter of 6 nm were successfully synthesized. The optical absorption edges of the thin ZnS nanorods were found to be blue-shifted compared with that of the bulk ZnS due to the quantum confinement effect.

A phospholipid-PEG2000 conjugate of a vascular endothelial growth factor receptor 2 (VEGFR2)-targeting heterodimer peptide for contrast-enhanced ultrasound imaging of angiogenesis

The transition of a targeted ultrasound contrast agent from animal imaging to testing in clinical studies requires considerable chemical development. The nature of the construct changes from an agent that is chemically attached to microbubbles to one where the targeting group is coupled to a phospholipid, for direct incorporation to the bubble surface. We provide an efficient method to attach a heterodimeric peptide to a pegylated phospholipid and show that the resulting construct retains nanomolar affinity for its target, vascular endothelial growth factor receptor 2 (VEGFR2), for both the human (kinase insert domain-containing receptor - KDR) and the mouse (fetal liver kinase 1 - Flk-1) receptors. The purified phospholipid-PEG-peptide isolated from TFA-based eluents is not stable with respect to hydrolysis of the fatty ester moieties. This leads to the time-dependent formation of the lysophospholipid and the phosphoglycerylamide derived from the degradation of the product. Purification of the product using neutral eluent systems provides a stable product. Methods to prepare the lysophospholipid (hydrolysis product) are also included. Biacore binding data demonstrated the retention of binding of the lipopeptide to the KDR receptor. The phospholipid-PEG2000-peptide is smoothly incorporated into gas-filled microbubbles and provides imaging of angiogenesis in a rat tumor model.

Resistance to Fusarium head blight and seedling blight in wheat is associated with activation of a cytochrome p450 gene

ABSTRACT One plant genotype displays a resistance phenotype at one development stage but a susceptible reaction to the same pathogen at another stage, which is referred to here as resistance inversion. In wheat, Fusarium head blight (FHB)-resistant cv. Sumai3 showed a Fusarium seedling blight (FSB)-susceptible reaction whereas FHB-susceptible cv. Annong8455 exhibited FSB resistance when challenged with a Fusarium asiaticum strain that produces deoxynivalenol (DON). The resistance to FHB and FSB in wheat was closely associated with expression of a plant cytochrome P450 gene in response to FHB pathogens and mycotoxins. Quantitative real-time polymerase chain reaction analyses showed that expression of nine defense-related genes in spikes and seedlings was induced by the fungal infection, in which a massive accumulation of a plant cytochrome P450 gene, CYP709C1, was clearly associated with the resistance reaction in both seedling and spike. The FHB-resistant Sumai3 accumulated 7-fold more P450 transcripts than did the FHB-susceptible Annong8455, while 84-fold more P450 transcripts were accumulated in the FSB-resistant Annong8455 than the FSB-susceptible Sumai3. A Fusarium strain with a disrupted Tri5 gene, which is not able to produce the first enzyme essential for trichothecene mycotoxin biosynthesis, also induced more P450 transcripts in FHB- and FSB-resistant cultivars. The fungal activation of the P450 gene was more profound in the FSB-resistant reaction than the FHB-resistant reaction relative to their susceptible counterparts. DON triggered a differential expression of the P450 gene with comparable patterns in spikes and seedlings in a resistance-dependent manner. These results may provide a basis for dissecting mechanisms underlying FHB and FSB resistance reactions in wheat and revealing functions of the cytochrome P450 in plant detoxification and defense.

Decision support for teletraining of COPD patients

BACKGROUND

Supervised physical training has been shown to promote rehabilitation of patients affected by chronic obstructive pulmonary disease (COPD). Currently, due to limited resources, not all COPD patients can be trained by an expert supervisor.

OBJECTIVES

The objective of our research is to construct a decision support system (DSS) which observes and controls physical ergometer training sessions of COPD patients.

METHODS

A systematic literature review and expert interviews were carried out to build up the knowledge base for the DSS.

RESULTS

Nine production rules were established and standardized by Drools and Arden Syntax. The developed software autonomously controls training sessions on a bicycle ergometer on the basis of vital signs data. Thus it offers a new way for the rehabilitation of COPD patients.

CONCLUSION

Evaluation with nine healthy subjects in a laboratory environment has confirmed its correct function, but the effects of its use for COPD patients' rehabilitation and their quality of life have to be investigated in a further study.

Roles of the primary cilium component Polaris in synchondrosis development

Primary cilia regulate several developmental processes and mediate hedgehog signaling. To study their roles in cranial base development, we created conditional mouse mutants deficient in Polaris, a critical primary cilium component, in cartilage. Mutant post-natal cranial bases were deformed, and their synchondrosis growth plates were disorganized. Expression of Indian hedgehog, Patched-1, collagen X, and MMP-13 was reduced and accompanied by decreases in endochondral bone. Interestingly, there was excessive intramembranous ossification along the perichondrium, accompanied by excessive Patched-1 expression, suggesting that Ihh distribution was wider and responsible for such excessive response. Indeed, expression of heparan sulfate proteoglycans (HS-PGs), normally involved in restricting hedgehog distribution, was barely detectable in mutant synchondroses. Analyses of the data provides further evidence for the essential roles of primary cilia and hedgehog signaling in cranial base development and chondrocyte maturation, and point to a close interdependence between cilia and HS-PGs to delimit targets of hedgehog action in synchondroses.

TAC (docetaxel, doxorubicin, and cyclophosphamide) adjuvant chemotherapy supported by G-CSF without dose-reduction in node-positive breast cancer

e11606

Background: For node-positive breast cancer, TAC (Docetaxel-Doxorubicin-Cyclophosphamide) chemotherapy is preferred as an adjuvant treatment. However, due to its high toxicity profiles such as severe neutropenia, TAC is a lot beyond enthusiasm. G-CSF support or even prophylaxis has been recommended to help patients recover from nadir, along with some dose-reduction schedule. We tried to evaluate whether TAC with G-CSF support from day 5 can be sustained without dose reduction in women under 69-years old. Methods: After getting IRB approval, between Mar. 2005 and Oct. 2008, 61 node-positive breast cancer patients (33 - 69 years old) had underwent TAC chemotherapy as an adjuvant treatment after curative resection after getting informed consent. Total of 366 cycles (6 cycles per patient, 75–50–500 mg/m2)were completed, G-CSF support was initiated from day 5 to full neutrophil recovery. In case of neutropenia, prophylactic antibiotics (cefoperazone 2 g and tobramycin 200 mg iv) were given. Results: Among 366 cycles, not a single cycle should be delayed to recover from any hematologic shortcomings such as neutropenia, anemia or thrombocytopenia. Interval of three weeks between each cycle could be maintained. No other problem happened for any patient to stop or postpone scheduled chemotherapy. None of antibiotics except prophylaxis with cefoperazone and tobramycin was needed. Conclusions: Maximum tolerable dose of chemotherapeutic agents should be given to patients to get the best oncologic outcome to fight against cancer. It is evident that huge scale prospective clinical trials can answer this question, but we presume that node-positive breast cancer patients between in her fourth and seventh decade can stand TAC chemotherapy with G-CSF support without dose reduction as routine.

No significant financial relationships to disclose.

Weight gain after adjuvant TAC (docetaxel, doxorubicin, and cyclophosphamide) chemotherapy for node-positive breast cancer

e11552

Background: Despite of its proven therapeutic efficacy, TAC (docetaxel, Doxorubicin and cyclophosphamide) regimen as an adjuvant chemotherapy has some serious adverse effects such as fluid retention and neutropenia. Even though dexamethasone is known to be given for three days to the patients having TAC chemotherapy to prevent severe fluid retention, most patients have ironically been complaining of much weight gain more than 15% increase after the use of dexamethasone. We tried to determine abbreviated use of dexamethasone is better to decrease the extent of weight gain after TAC chemotherapy. Methods: Eighty node-positive patients between Jan. 2006 and Oct. 2007 were randomly assigned either into 24-hr (group A: 10 mg dexamethasone the night before TAC, and 10 mg dexamethasone (bid) were given for the day 1) or 72-hr dexamethasone premedication (group B) only after getting informed consent since all the protocols were reviewed by IRB. We compared the incidence of severe weight gain (more than 15%) on completion of six cycles in two groups. No patient was found to have heart or kidney problem before the commencement of chemotherapy. Results: Each group was comprised of 40 patients. All patients underwent 6 cycles. Mean age of each group was 48.5 (A) and 50.3 (B) years. The incidence of severe weight gain was 47.3 % in Group A, and 78.4 % in Group B. There was no difference in the duration of recovering from weight gain in both groups (A: 6.52 months vs. B: 7.02 months). No other hematologic complications seemed different between two groups. Conclusions: Though larger scale prosepctive randomized trials should be required to get the definitive conclusion on this matter, we think that current dexamethasone premedication may aggravate weight gain than to prevent it. If shorter schedule is as much effective as longer one, abbreviated and reduced dexamethasone premedication is more helpful for patients having TAC chemotherapy.

No significant financial relationships to disclose.

Impacts of microRNA-215 on cell proliferation and chemotherapy resistance in colon cancer and osteosarcoma

2542

Background: Translational control plays a key role in resistance to anti-cancer drug treatment. MicroRNAs regulate gene expression at the post-transcriptional level, mainly by interacting with 3'-UTR of their mRNA targets. Methods: miR-215 was ectopically expressed by transient transfection in both human colon cancer cell lines and osteosarcoma cell lines. The impact of miR-215 on cell proliferation, cell cycle control, chemosensitivity and down stream targets were characterized. The expression of miR-215 in colorectal cancer specimens and normal adjacent tissues was quantified by real time-qRT-PCR analysis. Results: In this study, we discovered that miR-215 down-regulates the expression of both dihydrofolate reductase (DHFR) and thymidylate synthase (TS), two of the most important chemotherapeutic targets, in human osteosarcoma U-2 OS and colon cancer HCT-116 (wt-p53) cell lines. Cells with elevated miR-215 expression are more resistant to DHFR inhibitor methotrexate (MTX) or TS inhibitor Tomudex (TDX) treatment. Ectopically over-expressing miR-215 triggers reduced cell proliferation and increased G2 arrest, at least in part, through the induction of p53 and p21. miR-215 transfected cells with reduced proliferating phenotype were resist to MTX or TDX treatment due to deceased cell cycle in S phase. The expression of endogeneous miR-215 was highly elevated in CD133+/HI CD44+/HI colon cancer stem cells compared to CD133- CD44- colon cancer cells, suggesting that tumor stem cells may be avoiding cellular and DNA damage caused by chemotherapy with a reduced proliferating phenotype mediated by certain miRNAs such as miR-215. The elevated expression of miR-215 in colon cancer stem cells with slow proliferation rate and resistance to chemotherapy further supports the role of miR-215 in cell proliferation and chemotherapy resistance. Conclusions: miR-215 may have a unique potential as a novel therapeutic target and biomarker candidate in cancer.

No significant financial relationships to disclose.

TGFBR1 variants TGFBR1(*)6A and Int7G24A are not associated with an increased familial colorectal cancer risk

Variants of the transforming growth factor-beta receptor type 1 (TGFBR1) gene, TGFBR1*6A and Int7G24A, have been suggested to act as low-penetrance tumour susceptibility alleles with TGFBR1*6A being causally responsible for some cases of familial colorectal cancer (CRC). We performed a case–control study of 262 unrelated familial CRC cases; 83 hereditary non-polyposis colorectal cancer (HNPCC) and 179 non-HNPCC. Patients were genotyped for TGFBR1*6A and Int7G24A and compared with 856 controls. Further, we screened the coding region of TGFBR1 in affected members of a large family with CRC linked to 9q22.32-31.1. TGFBR1*6A allelic frequency was not significantly different in all of the familial cases compared with controls (0.107 and 0.106, respectively; P=0.915). In a subgroup analysis allele frequencies were, however, different between HNPCC and non-HNPCC familial cases (0.157 and 0.084, respectively; P=0.013). TGFBR1*6A genotype did not influence age of onset. Int7G24A allele frequencies were similar in cases and controls. No germ-line mutation was identified in the family with CRC linked to this chromosomal region. Our study provides no substantial support for the hypothesis that the polymorphic variants TGFBR1*6A or Int7G24A contribute to familial CRC risk. We cannot, however, exclude the possibility that TGFBR1 variants have a modifying effect on inherited risk per se.

Correction of congenital severe ptosis by suspension of a frontal muscle flap overlapped with an inferiorly based orbital septum flap

BACKGROUND

This report introduces a new method for correction of congenital severe upper eyelid ptosis.

METHODS

The poor levator-function upper eyelid ptosis of 22 patients was corrected using suspension of the frontal muscle flap overlapped with an inferiorly based orbital septum flap as a motor unit, which substituted for the function of the levator muscle. The frontal muscle flap and orbital septum flap were formed in the frontal part and upper eyelid, respectively. Two flaps were overlapped and sutured to suspend the upper eyelid and to correct the congenital severe upper eyelid ptosis. This technique avoids the need for the linking structure necessary with the standard frontalis sling approach and improves the direction of pull to mimic that of a normal levator more closely than that of frontalis muscle advancement.

RESULTS

The follow-up period ranged from 6 to 20 months (mean, 12 months). A total of 4 patients had bilateral surgery, whereas 18 patients underwent unilateral surgery (26 eyelids). In 22 cases (26 eyes), congenital severe upper eyelid ptosis was treated using suspension of the frontal muscle flap overlapped with an inferiorly based orbital septum flap. After the operation, 17 cases (19 eyes) were followed up and analyzed retrospectively. The average follow-up period was about 12 months (range, 6-20 months). The 17 corrected eyes had a symmetric redundant fold of preseptal skin according to the marginal reflex distance-1 (MRD-1) measurement used to judge efficacy. Two eyes in this series required reoperation for undercorrection. Complications such as ectropion and corneal exposure were avoided.

CONCLUSION

Use of a frontalis muscle lap overlapped with an inferior based orbital septum flap to manage severe congenital upper eyelid ptosis is a useful procedure that results in substantial cosmetic and functional improvement with few complications.

Mutations at arginine 352 alter the pore architecture of CFTR

Arginine 352 (R352) in the sixth transmembrane domain of the cystic fibrosis transmembrane conductance regulator (CFTR) previously was reported to form an anion/cation selectivity filter and to provide positive charge in the intracellular vestibule. However, mutations at this site have nonspecific effects, such as inducing susceptibility of endogenous cysteines to chemical modification. We hypothesized that R352 stabilizes channel structure and that charge-destroying mutations at this site disrupt pore architecture, with multiple consequences. We tested the effects of mutations at R352 on conductance, anion selectivity and block by the sulfonylurea drug glipizide, using recordings of wild-type and mutant channels. Charge-altering mutations at R352 destabilized the open state and altered both selectivity and block. In contrast, R352K-CFTR was similar to wild-type. Full conductance state amplitude was similar to that of wild-type CFTR in all mutants except R352E, suggesting that R352 does not itself form an anion coordination site. In an attempt to identify an acidic residue that may interact with R352, we found that permeation properties were similarly affected by charge-reversing mutations at D993. Wild-type-like properties were rescued in R352E/D993R-CFTR, suggesting that R352 and D993 in the wild-type channel may interact to stabilize pore architecture. Finally, R352A-CFTR was sensitive to modification by externally applied MTSEA+, while wild-type and R352E/D993R-CFTR were not. These data suggest that R352 plays an important structural role in CFTR, perhaps reflecting its involvement in forming a salt bridge with residue D993.

Orexin affects dorsal root ganglion neurons: a mechanism for regulating the spinal nociceptive processing

Orexins (orexin A and B) are initially known to be a hypothalamic peptide critical for feeding and normal wakefulness. In addition, emerging evidence from behavioral tests suggests that orexins are also involved in the regulation of nociceptive processing, suggesting a novel potential therapeutic approach for pain treatment. Both spinal and supraspinal mechanisms appear to contribute to the role of orexin in nociception. In the spinal cord, dorsal root ganglion (DRG) neurons are primary afferent neurons that transmit peripheral stimuli to the pain-processing areas. Morphological results show that both orexin A and orexin-1 receptor are distributed in DRG neurons. Moreover, by using whole-cell patch-clamp recordings and calcium imaging measurements we found that orexin A induced excitability and intracellular calcium concentration elevation in the isolated rat DRG neurons, which was mainly dependent on the activation of spinal orexin-1 receptor. Based on these findings, we propose a hypothesis that the direct effect of orexin A on DRG neurons would represent a possible mechanism for the orexinergic modulation of spinal nociceptive transmission.

Activating transcription factor 3 up-regulated by c-Jun NH(2)-terminal kinase/c-Jun contributes to apoptosis induced by potassium deprivation in cerebellar granule neurons

Cerebellar granule neurons (CGNs) depend on potassium depolarization for survival and undergo apoptosis when deprived of depolarizing concentration of potassium. Activating transcription factor 3 (ATF3), a stress-inducible protein, belongs to the ATF/CREB family of transcription factors family and is involved in cell growth and apoptosis. However, the role of ATF3 in neuronal apoptosis remains unknown. Here, we showed that ATF3 was up-regulated under potassium deprivation in CGNs, and this induction was preceded by a rapid and sustained activation of c-Jun NH(2)-terminal kinase/c-Jun signaling pathway, which plays a fundamental role in neuronal apoptosis. Furthermore, ATF3 up-regulation was abolished by inhibition of JNK or knockdown of c-Jun. Finally, knockdown of ATF3 by RNA interference protected CGNs from potassium deprivation-induced apoptosis. Taken together, our results indicate that ATF3 is a downstream target of JNK/c-Jun pathway and contributes to apoptosis induced by potassium deprivation in rat CGNs.

TGFBR1(*)6A and Int7G24A variants of transforming growth factor-beta receptor 1 in Swedish familial and sporadic breast cancer

Two common variants in transforming growth factor-β receptor 1 (TGFBR1), TGFBR1^*6A and Int7G24A, A allele, have been shown to act as low-penetrance tumour susceptibility alleles in several common cancers, including breast cancer. We evaluated the TGFBR1 9A/6A and Int7G24A variant frequencies in two breast cancer cohorts; a population-based cohort of breast cancer with defined family history (n=459) and in breast cancer patients from a familial cancer clinic (n=340) and in 856 controls from the Stockholm region. The familial patients from both cohorts were further divided into high- and low-risk familial breast cancer based on pedigree analysis. There was no overall association with either variant and breast cancer risk. The TGFBR1^*6A allelic frequency was, however, higher in low-risk familial breast cancer (0.138), compared to controls (0.106; P=0.04). No significant difference was found in the high-risk familial (0.102) or sporadic cases (0.109; P=0.83 and 0.83, respectively). TGFBR1^*6A carrier status was further associated with a high-grade sporadic breast cancer (odds ratio: 2.27; 95% confidence interval: 1.01–5.11; P=0.049). These results indicate that the TGFBR1^*6A variant may be associated with an increased risk of low-risk familial breast cancer and might be a marker for poorly differentiated breast cancer. The Int7G24A variant was not associated with breast cancer risk or clinical presentation of the disease including prognosis in our material.