Pharmacoproteomics: advancing the efficacy and safety of regenerative therapeutics

Proteomic analyses encompass a suite of high-throughput technologies for large-scale separation and identification of proteins responsible for execution of physiological processes. As such, proteomics is ideally suited to dissecting developmental complexity and dynamics, an understanding of which is vital to the realization of regenerative therapeutic medicine. Pharmacoproteomics is increasingly targeting characterization of regenerative therapeutic strategies. A perspective on the application of proteomics to further our understanding of cardiac regenerative medicine, in concert with guided cardiogenic programming, is delineated herein.

Effect of celecoxib on cyclooxygenase-2 expression and possible variants in a patient with Barrett's esophagus

Cyclooxygenase-2 (COX-2) expression is increased in metaplastic and dysplastic Barrett's esophageal epithelium and it is thought that selective COX-2 inhibitors could offer hope as chemoprevention therapy. The aim of the study was to investigate the in vivo effect of celecoxib on COX-2 expression in patients with Barrett's esophagus and no recent history of non-steroidal anti-inflammatory drug use. Endoscopic mucosal biopsy specimens were collected at baseline and after 28 days of therapy in a patient treated with celecoxib 200 mg twice daily. Samples were analyzed for COX-2 expression by immunoblot analysis with chemiluminescence detection. COX-2 expression was found to decline 20% and 44% at two different biopsy sites compared to the baseline sample. Longer exposures revealed a number of previously unidentified proteins above and below the 67 kDa COX-2 protein including 38 kDa and 45 kDa proteins which were present only at study completion consistent with up-regulation after celecoxib therapy. Further investigations of the 38 kDa and 45 kDa proteins were undertaken using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) with immunoblot and MALDI-TOF (matrix assisted laser desorption ionization - time of flight) analysis but no matches were found and results were inconclusive. Unmatched masses from MALDI-TOF peptide mass fingerprinting were compared with human COX-2 (67 kDa) and COX-2b (39 kDa) using unspecific cleavage. Peptide sequence homology with COX-2 and COX-2b was found for a length of 19 amino acids. Based on immunodetection, molecular weight and equivical MALDI-TOF results, one of these up-regulated proteins may be COX-2b.

N-cadherin signaling potentiates mammary tumor metastasis via enhanced extracellular signal-regulated kinase activation

N-cadherin is up-regulated in aggressive breast carcinomas, but its mechanism of action in vivo remains unknown. Transgenic mice coexpressing N-cadherin and polyomavirus middle T antigen (PyVmT) in the mammary epithelium displayed increased pulmonary metastasis, with no differences in tumor onset or growth relative to control PyVmT mice. PyVmT-N-cadherin tumors contained higher levels of phosphorylated extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) than PyVmT controls, and phosphorylated ERK staining was further increased in pulmonary metastases. Tumor cell isolates from PyVmT-N-cadherin mice exhibited enhanced ERK activation, motility, invasion, and matrix metalloproteinase-9 (MMP-9) expression relative to PyVmT controls. MAPK/ERK kinase 1 inhibition in PyVmT-N-cadherin cells reduced MMP-9 production and invasion but not motility. Furthermore, inactivation of fibroblast growth factor receptor in PyVmT-N-cadherin cells reduced motility, invasion, and ERK activation but had no effect on PyVmT cells. Thus, de novo expression of N-cadherin in mammary ducts enhances metastasis of breast tumors via enhanced ERK signaling.

Cognitive effects of lamotrigine compared with topiramate in patients with epilepsy

OBJECTIVE

To compare the cognitive effects of lamotrigine vs topiramate as adjunctive therapy in adults with epilepsy.

METHODS

A multicenter, double-blind, randomized, prospective study was conducted in adults with partial seizures. Lamotrigine or topiramate was introduced as an adjunctive therapy to carbamazepine or phenytoin and titrated over 8 weeks to target doses. These drugs were maintained another 8 weeks (maintenance phase) without dosage changes. The primary endpoint was change from screening to the end of the maintenance phase in a combined analysis of standardized measures of cognition (Controlled Oral Word Association Task [COWA]; Stroop Color-Word Interference; Digit Cancellation; Lafayette Grooved Pegboard, dominant hand; Rey Auditory Verbal Learning Test, delayed recall; and Symbol-Digit Modalities test).

RESULTS

For the primary endpoint, cognitive performance at the end of the maintenance phase was better with lamotrigine than with topiramate (415.3 vs 315.1; p < 0.001). On the individual cognitive tests, performance was better with lamotrigine than with topiramate in mean changes from screening on the COWA (p < 0.001), Stroop Color-Word Interference (p = 0.038), and Symbol-Digit Modalities tests (p < 0.001). The treatment effect exceeded the minimum clinically important difference for the COWA and the Symbol-Digit Modalities test. Mean changes from screening in the Performance-On-Line test simulating driving skills reflected better performance with lamotrigine than with topiramate (p = 0.021). The median percentage change from baseline in seizure frequency was lower with lamotrigine than with topiramate during the escalation phase (-80% vs -100%; p = 0.028) but not during the maintenance phase (-75% vs -100%; p = 0.062). The frequencies of cognitive adverse events and of premature withdrawals related to cognitive decline were higher with topiramate than with lamotrigine (6% vs 0%; p = 0.013).

CONCLUSION

Lamotrigine had significantly less impact than topiramate on measures of cognition when used as adjunctive therapy for partial seizures.

Genetic selection of sox1GFP-expressing neural precursors removes residual tumorigenic pluripotent stem cells and attenuates tumor formation after transplantation

Because of their ability to proliferate and to differentiate into diverse cell types, embryonic stem (ES) cells are a potential source of cells for transplantation therapy of various diseases, including Parkinson's disease. A critical issue for this potential therapy is the elimination of undifferentiated cells that, even in low numbers, could result in teratoma formation in the host brain. We hypothesize that an efficient solution would consist of purifying the desired cell types, such as neural precursors, prior to transplantation. To test this hypothesis, we differentiated sox1-green fluorescent protein (GFP) knock-in ES cells in vitro, purified neural precursor cells by fluorescence-activated cell sorting (FACS), and characterized the purified cells in vitro as well as in vivo. Immunocytofluorescence and RT-PCR analyses showed that this genetic purification procedure efficiently removed undifferentiated pluripotent stem cells. Furthermore, when differentiated into mature neurons in vitro, the purified GFP+ cell population generated enriched neuronal populations, whereas the GFP- population generated much fewer neurons. When treated with dopaminergic inducing signals such as sonic hedgehog (SHH) and fibroblast growth factor-8 (FGF8), FACS-purified neural precursor cells responded to these molecules and generated dopaminergic neurons as well as other neural subtypes. When transplanted, the GFP+ cell population generated well contained grafts containing dopaminergic neurons, whereas the GFP- population generated significantly larger grafts (about 20-fold) and frequent tumor-related deaths in the transplanted animals. Taken together, our results demonstrate that genetic purification of neural precursor cells using FACS isolation can effectively remove unwanted proliferating cell types and avoid tumor formation after transplantation.

Targeting bladder tumor cells in vivo and in the urine by a peptide identified using phage display

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Background: Bladder cancer is one of the most common tumors of genitourinary tract. Selective delivery of drugs to tumor tissues is important for effective tumor therapy. Here we identified a peptide targeting bladder tumor cells using phage display. Methods: Phage peptide library containing CX7C (C-cysteine and X-any amino acid residue) was based on T7 415–1b phage vector (Novagen). Tumor xenografts were prepared by subcutaneously injecting BALB/c Nu/nu female nude mice with HT-1376 bladder tumor cells. For a carcinogen-induced tumor model, Fischer 344 female rats were supplied ad libitum with tap water containing 0.05% N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) for 8 weeks. Results: A phage library containing CX7C random peptides was screened for selective binding to cells from human bladder tumor xenografts. Selected phage clones were individually evaluated for binding to cultured bladder tumor cells and for binding to cells from human tumor tissues of six patients. The peptide displayed by the most promising clone was synthesized and designated as Bld-1. Fluorescein-conjugated Bld-1 peptide showed selective binding to frozen sections of human bladder tumor tissues of three patients. In vivo tumor targeting was examined in a carcinogen-induced rat tumor model (n=20). When the fluorescent peptide was introduced into the bladder lumen, it selectively bound to tumor epithelium. Next, when the fluorescent peptide was intravenously injected into the tail vein, it homed to the bladder tumor, but was not detectable in normal bladder and control organs such as lung. Moreover, the fluorescent peptide bound to cells from urinary specimens of tumor patients (n=10), whereas little binding was observed in cells from healthy individuals (n=3). Conclusions: The Bld-1 peptide may be useful for targeting bladder tumor cells in vivo and in the urine.

No significant financial relationships to disclose.

Endoscopy-assisted ultrasonic surgical aspiration of axillary osmidrosis: a retrospective review of 896 consecutive patients from 1998 to 2004

Axillary osmidrosis is a distressing and troublesome problem that causes a serious handicap in personal and social life. Many different methods have been introduced to treat axillary osmidrosis, however, they are often accompanied by marked complications. We analysed our experiences using endoscopy-assisted ultrasonic surgical aspiration in treating the axillary osmidrosis. From June 1998 to February 2004, a total of 896 patients (562 females, 334 males) were treated for axillary osmidrosis using endoscopy-assisted ultrasonic surgical aspiration. Our method was satisfactory in 815 patients (91%) and recurrence of odour occurred only in 29 (3.2%) patients. It also showed complications in 28 (3.1%) patients. Our method leaves a small inconspicuous scar and no contracture of the axillary skin after a short and comfortable recovery period and maintains normal axillary hair growth patterns. Axillary osmidrosis can be best treated by endoscopy-assisted ultrasonic surgical aspiration and this operation has many advantages with a high success rate, a low complication rate, and a rapid recovery period.

Hospital planning for acts of terrorism and other public health emergencies involving children

In today's world the increased potential of terrorist attacks places unique burdens and consequences on health care workers. Hospitals and hospital personnel must now be prepared to react immediately to such events. They must also implement, in advance, policies to protect their own health care personnel while providing care to victims. In this review, we discuss the four major forms of mass casualty terrorism (biological, chemical, nuclear, and thermomechanical) including clinical signs and symptoms for each, the impact on health care personnel, and special considerations for children. We will then outline key principles of hospital preparation with regard to paediatrics in anticipation of such emergencies.

Widespread endoscopic mucosal resection of the esophagus with strategies for stricture prevention: a preclinical study

BACKGROUND AND STUDY AIMS

Circumferential endoscopic mucosal resection of the esophagus is complicated by stricture formation. Prophylactic measures for avoiding such strictures have not been well studied. The aim of this preclinical study was to assess strategies for prevention of esophageal strictures in a porcine model following widespread endoscopic mucosal resection (EMR).

METHODS

A total of 18 60-kg pigs were included in the study. The roles of strip width (group 1), prophylactic steroids (group 2), and prophylactic stents (group 3) in the prevention of post-mucosectomy strictures were studied. Six animals were included in each group. Esophageal mucosal resection was achieved using a novel widespread EMR technique previously described by our group. Animals in group 1 underwent partial (50% circumference) mucosal resection without prophylactic measures, while animals in the other two groups underwent circumferential mucosal resection. Animals in group 2 received 80 mg of triamcinolone injected directly into the exposed submucosal tissue (20 mg injection in four quadrants). Animals in group 3 received esophageal metal stents coated with small-intestine submucosa (SIS) that were deployed immediately post-resection. Animals were kept alive for 1 month.

RESULTS

Partial and circumferential widespread EMRs were achieved in all animals. There were no procedural complications. Repeat endoscopy at 1 month showed no strictures in group 1. Only four animals were studied in group 2, owing to the high complication rate (periesophageal abscess in all animals) with one early death. Three of the surviving animals developed mild to tight strictures. In group 3, all animals developed tight strictures; however, there was early stent migration in four animals and premature stent removal in two animals because of persistent vomiting.

CONCLUSIONS

Partial widespread EMR of the esophagus heals without stricture formation and does not require prophylactic intervention. The use of deep mural steroid injection following a circumferential resection does not appear to prevent strictures and may result in serious adverse events. Short-term use of esophageal stents is inadequate for stricture prevention. However, better results may be anticipated with longer term (at least 6 weeks) stent use.

Isolation and characterization of CO2-fixing hydrogen-oxidizing marine bacteria

A CO2-fixing bacterium, strain YN-1, that can fix CO2 under chemoautotrophic conditions but not photoautotrophic conditions was isolated from seawater. Identification of the isolate was carried out using biochemical tests and 16S rDNA sequence analysis, and its characteristics were investigated. From the results of partial 16S rDNA sequence analysis, strain YN-1 showed low identity with previously reported hydrogen-oxidizing bacteria, Hydrogenovibrio marinus MH-110 and Hydrogenophilus thermoluteolus. This result indicates that strain YN-1 may be a new hydrogen-oxidizing marine bacterium. Strain YN-1 showed considerable CO2 fixation ability during continuous cultivation even at high CO2 concentration. Strain YN-1 used H2 and CO2 as energy and carbon sources, respectively. Growth characteristics were examined in batch and continuous cultivation with a view to improving the CO2 fixation rate. The results showed that CO2 fixation occurred in the absence of a light source and that the strain exhibited good growth at high CO2 concentration (40%). On the other hand, the dry cell weight was 13.4 g/l following continuous cultivation for 76 h in 10% CO2 (0.1 l/min), and at that time the amount of fixed CO2 was 18.08 g CO2/l. This indicates that strain YN-1 can efficiently fix CO2 even at high CO2 concentrations, which would allow its application to the removal of industrially discharged CO2.