The effects of media properties on the horseradish peroxidase-catalyzed fluorogenic reaction

The effects of media properties including buffers, acidity, solvents and surfactant on horseradish peroxidase-catalyzed fluorogenic reaction were investigated. The results showed that the so-called non-fluorescent hydrogen donors were in fact fluorescent. There existed an acid-base equilibrium in the fluorescent dimer product. For p -hydroxyphenylpropionic acid, a pK(a) value of 8.0 for the product was obtained from its titration curve. The product fluorescence increased with higher pH, however, a longer time was needed to reach the reaction equilibrium due to the pH mismatch problem. Cationic micelles cetyltrimethylammonium bromide and cetyltrimethylammonium chloride could reduce the pH mismatch and offered a way to further increase the determination sensitivity. Finally, a micelle-enhanced flow-injection analysis of horseradish peroxidase is suggested.

Hyperspectral imaging and quantitative analysis for prostate cancer detection

Hyperspectral imaging (HSI) is an emerging modality for various medical applications. Its spectroscopic data might be able to be used to noninvasively detect cancer. Quantitative analysis is often necessary in order to differentiate healthy from diseased tissue. We propose the use of an advanced image processing and classification method in order to analyze hyperspectral image data for prostate cancer detection. The spectral signatures were extracted and evaluated in both cancerous and normal tissue. Least squares support vector machines were developed and evaluated for classifying hyperspectral data in order to enhance the detection of cancer tissue. This method was used to detect prostate cancer in tumor-bearing mice and on pathology slides. Spatially resolved images were created to highlight the differences of the reflectance properties of cancer versus those of normal tissue. Preliminary results with 11 mice showed that the sensitivity and specificity of the hyperspectral image classification method are 92.8% to 2.0% and 96.9% to 1.3%, respectively. Therefore, this imaging method may be able to help physicians to dissect malignant regions with a safe margin and to evaluate the tumor bed after resection. This pilot study may lead to advances in the optical diagnosis of prostate cancer using HSI technology.

Abstract 4498: Prognostic significance of nuclear factor kappa B expression in human papillomavirus-associated oropharyngeal cancer

Nuclear factor kappa B (NFκB) has been implicated in the development of head and neck squamous cell carcinoma (HNSCC) from premalignant changes to tumor progression and recurrence. However, the prognostic significance of cytoplasmic or nuclear localization of NFκB expression in human papillomavirus (HPV)-associated HNSCC has not been investigated largely due to limited patient samples. We hypothesized that cytoplasmic and/or nuclear expression of NFκB may be a poor prognostic factor for tumor recurrence and overall survival (OS) regardless of p16 status. We conducted a retrospective study with archival formalin-fixed paraffin-embedded tumor biopsies collected from 188 patients with oropharyngeal SCC between October 1994 and February 2008 from Emory University Department of Pathology. Median follow-up was 21.7 and 58.0 months for p16- and p16+ patients, correspondingly. Tumors were evaluated for p16 expression (a surrogate marker for HPV) by immunohistochemistry (IHC). Cytoplasmic expression of NFκBp65 by IHC or total expression combining cytoplasmic and nuclear localization were significantly greater in p16- patients (N=58) than p16+ patients (N=130), p<0.05. High cytoplasmic expression of NFκBp65 was significantly associated with poor OS (p=0.0276) and the total expression was associated with recurrence (p=0.0081) by log rank test, whereas nuclear NFκBp65 displayed weak association. Positive nuclear expression significantly correlated with smoking history (p=0.025). In conclusion, p16+ and low total NFκBp65 expression is associated with the best while p16- and high total NFκBp65 is associated with the worst OS in this patient cohort (Table I). (The study was supported by Head and Neck SPORE Grant P50CA128613).

Increased expression of Rab coupling protein in squamous cell carcinoma of the head and neck and its clinical significance

The role of Rab coupling protein (RCP) has not been previously investigated in squamous cell carcinoma of the head and neck (SCCHN). The aim of this study was to explore RCP protein expression and its clinicopathological significance in SCCHN. RCP protein expression in 95 SCCHN samples, 18 vocal nodule epithelia and 16 leukoplakia epithelia samples was analyzed by immunohistochemistry and correlated with clinicopathological parameters and patient outcome. Our data indicated that vocal nodule epithelia, leukoplakia epithelia and SCCHN showed a gradual increase in the expression of RCP protein. RCP overexpression was significantly associated with T classification, clinical staging, lymph node metastasis and recurrence. Survival analysis revealed that a high RCP expression was significantly correlated with shorter overall survival and disease-free survival. In conclusion, RCP protein may contribute to the malignant progression of SCCHN, and serves as a novel prognostic marker in patients with SCCHN.

Tyrosine phosphorylation of mitochondrial pyruvate dehydrogenase kinase 1 is important for cancer metabolism

Many tumor cells rely on aerobic glycolysis instead of oxidative phosphorylation for their continued proliferation and survival. Myc and HIF-1 are believed to promote such a metabolic switch by, in part, upregulating gene expression of pyruvate dehydrogenase (PDH) kinase 1 (PDHK1), which phosphorylates and inactivates mitochondrial PDH and consequently pyruvate dehydrogenase complex (PDC). Here we report that tyrosine phosphorylation enhances PDHK1 kinase activity by promoting ATP and PDC binding. Functional PDC can form in mitochondria outside of the matrix in some cancer cells and PDHK1 is commonly tyrosine phosphorylated in human cancers by diverse oncogenic tyrosine kinases localized to different mitochondrial compartments. Expression of phosphorylation-deficient, catalytic hypomorph PDHK1 mutants in cancer cells leads to decreased cell proliferation under hypoxia and increased oxidative phosphorylation with enhanced mitochondrial utilization of pyruvate and reduced tumor growth in xenograft nude mice. Together, tyrosine phosphorylation activates PDHK1 to promote the Warburg effect and tumor growth.

Analysis of transcriptional factors and regulation networks in laryngeal squamous cell carcinoma patients with lymph node metastasis

The present study was to identify and quantitate differentially expressed proteins in laryngeal squamous cell carcinoma (LSCC) tissues with or without lymph node metastasis and to explore transcriptional factors and regulation networks associated with the process. Tissue specimens were taken from 20 patients with LSCC, including 10 cases of LSCC without metastasis LSCC (N0) and 10 cases of LSCC with metastasis LSCC (Nx). Among the 643 unique proteins identified by using iTRAQ labeling and quantitative proteomic technology, 389 proteins showed an abundance change in LSCC (Nx) as compared to LSCC (N0). Cytoskeleton remodeling, cell adhesion, and immune response activation were found to be the main processes in LSCC metastasis. The construction of transcription regulation networks identified key transcription regulators for lymph node metastasis of LSCC, including Sp1, c-myc, and p53, which may affect LSCC metastasis through the epithelial-mesenchymal transition. Furthermore, our results suggest that ubiquitination may be a critical factor in the networks. The present study provides insights into transcriptional factors and regulation networks involved in LSCC metastasis, which may lead to new strategies for treatment of LSCC metastasis.

Abstract 2342: RSK2 phosphorylates and activates CREB to promote HNSCC cell invasion through upregulation of pro-metastatic MCAM and Fascin-1

Head and neck squamous cell carcinoma (HNSCC) is one of the most common types of human cancer and clinically effective treatment of HNSCC remains difficult due to metastasis. Therefore, it is of immerse clinical interest to identify metastasis-promoting genes in HNSCC tumors to improve prognosis and define targets for therapy. We recently reported that continued expression of p90 Ribosomal S6 kinase 2 (RSK2) contributes to the maintenance of the invasive and metastatic potential of HNSCC cells in vitro and in vivo, respectively. By a phospho-proteomics based study using a phospho-antibody microarray, we identified a spectrum of pro-metastatic proteins whose phosphorylation levels are regulated by RSK2 in HNSCC cells, including CREB, Hsp27, c-Jun, Elk-1, FAK, IRS-1, Jun-B, c-MET, and Stathmin.

CREB is a transcription factor and RSK2 activates CREB by phosphorylating CREB Ser133. To explore the molecular mechanism underlying the RSK2→CREB pathway-mediated pro-invasive signals, we surveyed potential links between RSK2 and known CREB transcription targets that are implied in cell invasion and tumor metastasis, including HPSE-1, IRS-2, MMP2, VEGF, CNN/Cyr61, MCAM, and Fascin-1. RT-PCR results showed that stable knockdown of RSK2 in highly invasive HNSCC cells results in decreased mRNA levels of VEGF, MCAM and Fascin-1. MCAM (melanoma cell adhesion molecule) is one of the immunoglobulin superfamily which is known to be involved in focal adhesion assembly and cell migration. Fascin-1 is a critical hallmark of the invasive phenotype in cancer cells which bundles F-actin and contributes to cell migration and invasion. Using real-time RT-PCR, we confirmed that stable knockdown of RSK2 result in significant decrease in mRNA levels of MCAM and Fascin-1 in the RSK2-expressing, highly invasive HNSCC M4e, 212LN and 37B cells. Moreover, targeting MCAM and Fascin-1 by shRNA in 212LN cells led to significantly increased cell sensitivity to detachment-induced anoikis, which correlated with attenuated cell invasive potential of these cells. In addition, overexpression of MCAM and Fascin-1 in 212LN cells with stable knockdown of RSK2 rescued phenotypes due to lack of RSK2, resulting in increased cell invasion and reduced cell sensitivity to anoikis, compared to RSK2 knockdown cells.

These data together suggest a transcription-dependent mechanism in which RSK2 may signal through CREB to provide anti-anoikis signals and promote HNSCC cell invasion, in part by up-regulated pro-metastatic proteins such as MCAM and Fascin-1. Our studies may shed new insights into understanding of molecular mechanisms underlying HNSCC metastasis and development of novel therapeutic strategies to treat metastatic HNSCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2342. doi:10.1158/1538-7445.AM2011-2342

c-Jun NH2-terminal kinase-dependent upregulation of DR5 mediates cooperative induction of apoptosis by perifosine and TRAIL

BACKGROUND

Perifosine, an alkylphospholipid tested in phase II clinical trials, modulates the extrinsic apoptotic pathway and cooperates with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) to augment apoptosis. The current study focuses on revealing the mechanisms by which perifosine enhances TRAIL-induced apoptosis.

RESULTS

The combination of perifosine and TRAIL was more active than each single agent alone in inducing apoptosis of head and neck squamous cell carcinoma cells and inhibiting the growth of xenografts. Interestingly, perifosine primarily increased cell surface levels of DR5 although it elevated the expression of both DR4 and DR5. Blockade of DR5, but not DR4 upregulation, via small interfering RNA (siRNA) inhibited perifosine/TRAIL-induced apoptosis. Perifosine increased phosphorylated c-Jun NH2-terminal kinase (JNK) and c-Jun levels, which were paralleled with DR4 and DR5 induction. However, only DR5 upregulaiton induced by perifosine could be abrogated by both the JNK inhibitor SP600125 and JNK siRNA. The antioxidants, N-acetylcysteine and glutathione, but not vitamin C or tiron, inhibited perifosine-induced elevation of p-c-Jun, DR4 and DR5. Moreover, no increased production of reactive oxygen species was detected in perifosine-treated cells although reduced levels of intracellular GSH were measured.

CONCLUSIONS

DR5 induction plays a critical role in mediating perifosine/TRAIL-induced apoptosis. Perifosine induces DR5 expression through a JNK-dependent mechanism independent of reactive oxygen species.

Therapeutic Nanoparticles as Controlled Anti-Cancer Medications

The development of therapeutic nanoparticles (TNPs) for cancer treatment is one of the fastest growing research areas in oncology. Accumulating evidence has shown many advantages of TNPs over freely delivered chemotherapeutic drugs, such as enhanced water solubility, tumor-specific accumulation, and antitumor efficacy, while at the same time reducing non-specific tumor toxicity. However, the mechanisms behind these observations and outcomes have not been fully elucidated. Major challenges for applying TNPs in the clinic are to understand precisely how chemotherapeutic agents are released from TNPs and delivered to the targeted tumor tissues/cells, and how the TNPs' biodistribution affects toxicity in major organs. This review focuses on recent exploration of these unresolved issues with comparisons between free drugs and TNPs and between targeted and non-targeted TNPs. Several well-developed TNPs with unique characteristics will be discussed. Their specific applications for the treatment of certain cancer types have shed light on the clinical use of TNPs in cancer therapy.

The role of radial oxygen loss and root anatomy on zinc uptake and tolerance in mangrove seedlings

Root anatomy, radial oxygen loss (ROL) and zinc (Zn) uptake and tolerance in mangrove plants were investigated using seedlings of Aegiceras corniculatum, Bruguiera gymnorrhiza and Rhizophora stylosa. The results revealed that B. gymnorrhiza, which possessed the 'tightest barrier' in ROL spatial patterns among the three species studied, took up the least Zn and showed the highest Zn tolerance. Furthermore, zinc significantly decreased the ROL of all three plants by inhibition of root permeability, which included an obvious thickening of outer cortex and significant increases of lignification in cell walls. The results of SEM X-ray microanalysis further confirmed that such an inducible, low permeability of roots was likely an adaptive strategy to metal stress by direct prevention of excessive Zn entering into the root. The present study proposes new evidence of structural adaptive strategy on metal tolerance by mangrove seedlings.

Abstract 34: Oncogenic tyrosine kinases phosphorylate and inhibit PKM2 to provide a metabolic advantage to tumor growth

Cancer cells show increased aerobic glycolysis and enhanced lactate production compared to healthy cells, a phenomenon known as the Warburg effect. Cell surface growth factor receptors, which often carry tyrosine kinase activities in their cytoplasmic domains, are overexpressed in many human cancers and are believed to play a key role in determining cell metabolism. Thus, we explored the hypothesis that tyrosine kinase signaling, which is commonly increased in tumors, regulates the Warburg effect and contributes to tumorigenesis and maintenance of the tumor.

We performed phospho-proteomics studies and found that oncogenic forms of fibroblast growth factor (FGF) receptor type 1 (FGFR1) inhibit the pyruvate kinase M2 isoform (PKM2) in cancer cells. Pyruvate kinase is a rate-limiting enzyme during glycolysis and catalyzes the production of pyruvate and ATP from phosphoenolpyruvate (PEP) and ADP. Recent studies demonstrated that the enzymatic activity of the pyruvate kinase M2 isoform (PKM2) is inhibited by phosphotyrosine binding; moreover, these researchers found that PKM2 is crucial for aerobic glycolysis and provides a growth advantage to tumors. However, it remains unclear which tyrosine kinase pathways are physiologically responsible for this inhibition of PKM2 activity and which protein factors undergo tyrosine phosphorylation, allowing them to bind to and thereby inhibit PKM2. We found that PKM2 is itself tyrosine phosphorylated in cancer cells and such a physiological modification of PKM2 promotes the switch to aerobic glycolysis from oxidative phosphorylation. FGFR1 directly phosphorylates PKM2 at tyrosine residue 105 (Y105). This inhibits the formation of active, tetrameric PKM2 by disrupting binding of the PKM2 cofactor fructose-1,6-bisphosphate (FBP). Moreover, we found that phosphorylation of PKM2 Y105 is common in human cancers. Immunoblotting revealed that PKM2 is phosphorylated at Y105 in diverse human breast cancer, lung cancer, prostate cancer and leukemia cell lines. Oncogenic tyrosien kianses including BCR-ABL, FLT3-ITD and JAK2 also directly phosphorylate PKM2 Y105 in in vitro kinase assays using purified proteins. Furthermore, the presence of a PKM2 mutant in which phenylalanine is substituted for Y105 (Y105F) in cancer cells leads to decreased cell proliferation under hypoxic conditions, increased oxidative phosphorylation with reduced lactate production, and reduced tumor growth in xenografts in nude mice.

Our findings suggest that tyrosine phosphorylation regulates PKM2 to provide a metabolic advantage to tumor cells, thereby promoting tumor growth. This may represent a common, short-term molecular mechanism underlying the Warburg effect in both leukemias and solid tumors, in addition to the chronic changes believed to be regulated by transcription factors, including hypoxia inducible factor 1 and Myc.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 34.

Abstract 2257: Optical imaging guidance of tumor resection margin for head and neck cancer

Traditional methods for assessing adequacy of head and neck tumor resection rely upon intraoperative palpation or visualization. Positive margins are strongly associated with recurrence and poor patient survival. To ensure the complete tumor removal, surgeons may resect additional peritumoral tissues. During the past decade, intraoperative pathologic consultation by frozen section has become standard. Each round of consultation takes 20 minutes and the average number of such consultation is 3 − 4 per operation, which prolongs the procedure. Two additional potential problems are: (1) it is impossible to locate all cohorts of infiltrating tumor cells; (2) the final pathology may reveal a positive margin when the frozen section was negative. Currently 20 − 30% of head and neck patients that undergo surgery still leave the operating room with an incomplete resection. Thus, major opportunities exist to develop a deep tissue imaging near infrared (NIR) agent and an intraoperative instrumentation that would allow surgeons to visualize microscopic tumors during surgery. The advantage of using optical imaging over radioisotopes is that it avoids continuous exposure of operating room personnel to radioactivity. The cell adhesion molecule integrin αvβ3 is specifically expressed by tumor neovasculature and invading tumor cells, but not by quiescent vessels or normal cells. We exploited integrin overexpression on infiltrating cancer cells for intraoperative detection of tumor margins. We tested a new optical instrumentation in conjunction with the integrin-targeted NIR dye, RGD-IRDye800CW, for assessing malignant tumor margins in an orthotopic head and neck cancer animal model. RGD peptides have high binding specificity to integrin αvβ3. For intraoperative tumor margin detection, we developed an intraoperative wavelength-resolved NIR imaging system. This device offers real-time, portable detection of tumor margins with high stability, faster throughput, and better co-registration than other imaging methods. In our animal model, the tumors infiltrated to the mylohoid neck muscle beyond tumor boundaries and the primary tumor resection left residual infiltrating tumors and metastatic lymph nodes behind, which were easily detected by our technology. We also found NIR signal in several spots of the lungs from the same mice. Histological analysis in correlation to imaging results support that we can detect extremely small cohorts of 20 − 50 tumor cells in intraoperative settings with high specificity. Thus our technology will be ideal in detecting tumor margins intraoperatively because the average number of tumor cells in invading cohorts is 50 − 100 and NIR penetration depth is about 3 − 5 cm. Of note, we found that NIR signals from the RGD peptides were stronger at the edge (rim) of tumors than the center; therefore, the integrin-targeted imaging probe will allow us to detect the tumor margins as well as infiltrating cohorts of tumor cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2257.

Abstract 1260: Analysis of death receptor 5 and caspase-8 expression in primary and metastatic head and neck squamous cell carcinoma and their prognostic impact

Death receptor 5 (DR5) and caspase-8 are major components in the extrinsic apoptotic pathway. The alterations of the expression of these proteins during the metastasis of head and neck squamous cell carcinoma (HNSCC) and their prognostic impact have not been reported. The present study analyzes the expression of DR5 and caspase-8 by immunohistochemistry (IHC) in primary and metastatic HNSCCs and their impact on patient survival. Tumor samples in this study included approximately 90 primary HNSCC with no evidence of metastasis and approximately 90 primary HNSCC and their matching lymph node metastasis. IHC analysis revealed a significant loss or downregulation of DR5 expression in primary tumors with metastasis [weight index (WI) = 221 ± 64.9 (mean ± SD), n = 92] and their matching lymph node metastasis (WI = 224 ± 71.6, n = 85) compared to primary tumors with no evidence of metastasis (WI = 250 ± 43.9, n = 94) (P < 0.01). A similar trend was also observed in caspase-8 expression although it is not statistically significant. Downregulation of caspase-8 and DR5 expression was significantly correlated with poorly differentiated tumors compared to moderately and well differentiated tumors (P < 0.05). Univariate analysis indicates that, in HNSCC with no metastasis, higher expression of caspase-8 significantly correlated with better disease-free survival and overall survival (P < 0.05 or 0.001) if mean value is used as a cutoff. However, in HNSCC with lymph node metastasis, higher caspase-8 expression significantly correlated with poorer disease-free survival and overall survival (< 0.05 or 0.01). Similar results were also generated when we combined both DR5 and caspase-8. Moreover, multivariable analysis indicates that in patients without lymph node metastasis, high caspase-8 is significantly associated with better survival after adjusting age and stage (P < 0.0001). Together, we suggest that both proteins may be involved in regulation of HNSCC metastasis. (G.C., D.M.S., F.R.K. and S-Y.S. are Georgia Cancer Coalition Distinguished Cancer Scholars. This study was supported by funds from the Georgia Cancer Coalition Distinguished Cancer Scholar and NIH Head and Neck SPORE P50 CA128613 awards)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1260.

Tyrosine phosphorylation inhibits PKM2 to promote the Warburg effect and tumor growth

The Warburg effect describes a pro-oncogenic metabolism switch such that cancer cells take up more glucose than normal tissue and favor incomplete oxidation of glucose even in the presence of oxygen. To better understand how tyrosine kinase signaling, which is commonly increased in tumors, regulates the Warburg effect, we performed phosphoproteomic studies. We found that oncogenic forms of fibroblast growth factor receptor type 1 inhibit the pyruvate kinase M2 (PKM2) isoform by direct phosphorylation of PKM2 tyrosine residue 105 (Y(105)). This inhibits the formation of active, tetrameric PKM2 by disrupting binding of the PKM2 cofactor fructose-1,6-bisphosphate. Furthermore, we found that phosphorylation of PKM2 Y(105) is common in human cancers. The presence of a PKM2 mutant in which phenylalanine is substituted for Y(105) (Y105F) in cancer cells leads to decreased cell proliferation under hypoxic conditions, increased oxidative phosphorylation with reduced lactate production, and reduced tumor growth in xenografts in nude mice. Our findings suggest that tyrosine phosphorylation regulates PKM2 to provide a metabolic advantage to tumor cells, thereby promoting tumor growth.

Uptake and accumulation of arsenic by 11 Pteris taxa from southern China

A field survey was conducted at a deserted arsenic (As) mine in Guangxi Province, China to explore new potential As hyperaccumulators. In addition, young plants of 11 Pteris taxa were grown in glasshouse conditions for 12 weeks on As-amended soils with 0, 50 and 200 mg As kg(-1). Results of the field survey showed that the fern Pteris fauriei accumulated over 1000 mg As kg(-1) in its fronds. Of the 11 Pteris taxa, Pteris aspericaulis, Pteris cretica var. nervosa, P. fauriei, Pteris multifida, P. multifida f. serrulata, and Pteris oshimensis were all found to hyperaccumulate As in addition to P. cretica 'Albo-Lineata' and Pteris vittata (already reported as As hyperaccumulators). However, Pteris ensiformis, Pteris semipinnata and Pteris setuloso-costulata showed no evidence of As hyperaccumulation. Results also revealed a constitutive property of As hyperaccumulation in different populations of P. cretica var. nervosa, P. multifida, P. oshimensis and P. vittata.

Combined neuroform intracranial stent and bioactive matrix detachable coil for embolization of a broad-necked persistent primitive trigeminal artery aneurysm. A case report

SUMMARY

We report a patient with a wide-necked aneurysm arising at the bifurcation of the right internal carotid artery and the persistent primitive trigeminal artery (PPTA) treated successfully by Matrix detachable coil occlusion and assisted by a Neuroform intracranial stent. First, a Neuroform self-expanding intracranial stent was delivered via a 5-F Guider Softtip XP and placed as desired, then the aneurysm dome was embolized with two Matrix detachable coils through the interstices of the stent. The aneurysm was 80% occluded angiographically and the parent artery was patent. DSA imaging six months after the procedure showed the aneurysm to be obliterated at angiography and the neck tissue thickness of the aneurysm to be increased, but the parent artery diameter was not impacted. We describe the case in detail and discuss our preliminary experience of using the Neuroform stent and Matrix detachable coils for the treatment of a PPTA wide-necked aneurysm.

The metalloprotease inhibitor 1,10-phenanthroline affects Schistosoma mansoni motor activity, egg laying and viability

The Zn(2+)-chelating metalloprotease inhibitor 1,10-phenanthroline (phenanthroline, 5-150 microM) elicited dose-dependent contraction of the longitudinal and circular (transverse) musculature of adult male schistosomes. At the same concentrations, phenanthroline did not cause contraction of dispersed individual muscle fibres. The phenanthroline-induced contractions were reduced by the inclusion of 100 or 300 microM Zn2+ in the extracellular medium. Phenanthroline (0.5-150 microM) also inhibited the egg production of adult worm pairs in vitro, with a 98% reduction at 50 microM. When worm pairs were exposed to phenanthroline, the males detached from the dish and released the females, resulting in unpaired worms. At the higher concentrations (50 and 150 microM), the worms were killed in vitro. Worm burdens were reduced by over 50% in infected mice injected with phenanthroline (20 mg/kg/day for 4 days), but twice the dose resulted in only a 25% reduction. Phenanthroline injections also induced an hepatic shift and an unpairing of adult worms in infected mice, and the female worms appeared degenerate and lacked gut pigmentation. Mice fed a diet containing 0.3% phenanthroline received significant protection from infection when challenged with schistosome cercaria, where phenanthroline-fed mice had 94% fewer adult worms than control mice. The broad range of phenanthroline effects on schistosomes suggests broad and important functions for metalloproteases in these worms.

Cholinergic inhibition of muscle fibres isolated from Schistosoma mansoni (Trematoda:Digenea)

Cholinergic compounds inhibit FMRFamide-induced contractions in dispersed muscle fibres isolated from adult Schistosoma mansoni. Acetylcholine (ACh) was the most effective cholinergic agonist tested with an EC50 < 100 nM. Less effective were propionylcholine and arecoline with EC50 < 1 microM and butyrylcholine and carbachol with EC50 < 10 microM. Choline, muscarine, pilocarpine, nicotine, DMPP (1,1-dimethylphenylpiperazine) and levamisole were all ineffective. Amongst tested antagonists, d-tubocurarine (100 microM), mecamylamine (1 mM), scopolamine (1 mM) and quinuclidinyl benzilate (10 microM) were all ineffective. Bicuculline, picrotoxin and strychnine were also ineffective. However alpha-bungarotoxin, at 100 nM, was able to block the inhibitory ACh effect. From these data it appears that the cholinergic receptor on the schistosome muscle fibres may be of the nicotinic type, but that its pharmacology is different from that of nicotinic receptors of vertebrates as well as of nematodes or a variety of other invertebrates.

[Effect of jiawei sijunzi decoction on migrating myoelectric complex in 8 Gy irradiated rats]

The normal intestinal migrating myoelectric complex (MMC) of rats recorded by implanted electrode consists of four phases (phase I, II, III and IV). After 8 Gy of gamma-radiation for 1 hour to 7 days, the MMC cycle in most of the rats were disappeared only phase I or II existed with minute's rhythm. 1 hour or 3 days after radiation, the MMC cycle appeared in a few rats with the phase II shortened significantly (P < 0.05). Results of observation on effect of Jiawei Sijunzi Decoction on MMC after radiation showed the changed phase and cycle of MMC were normalized basically by the medication. These results suggested that the Jiawei Sijunzi decoction could improve the intestinal disturbances caused by radiation, it might be one of the reason of its alleviating effect on the radiation diarrhea.

Immunohistochemical localization of a Shaker-related voltage-gated potassium channel protein in Schistosoma mansoni (Trematoda: Digenea)

We have recently isolated a cDNA (SKv1.1) encoding a Shaker-related K+ channel from the human parasitic trematode Schistosoma mansoni. In order to better understand the functions of SKv1.1 protein, the distribution of SKv1.1 protein in adult S. mansoni was analyzed by immunohistochemistry using a region-specific antibody. SKv1.1 proteins were widely expressed in the nervous and muscular systems. The strongest immunoreactivity (IR) was observed in the nervous system of both male and female. In the nervous system, IR for SKv1.1 proteins was localized in cell bodies and nerve fibers of the anterior ganglia, the central commissure, and the main nerve cords. IR was also observed in the dorsal and the ventral peripheral nerve nets, fine nerve fibers entering into a variety of structures such as the dorsal tubercles, longitudinal and ventral muscle fibers, and oral and ventral suckers. In the muscular system, SKv1.1 proteins were localized to the longitudinal, circular, and ventral muscle fibers of male as well as in isolated muscle fibers where native A-type K+ currents were measured. Moderate IR was also seen in a large number of cell bodies in the parenchyma. These results indicate that SKv1.1 protein may play an important role in the regulation of the excitability of neurons and muscle cells of S. mansoni.

Restriction fragment length polymorphism of the apolipoprotein B gene and response to dietary fat and cholesterol

OBJECTIVE

The relationship between response to dietary fat and cholesterol, and the EcoRI restriction fragment length polymorphism (RFLP) of the apolipoprotein B(apoB) gene was examined.

DESIGN

Forty-nine free-living subjects took part in a prospective double-blind crossover dietary intervention study. The apoB EcoRI cutting site was present in five women and 18 men (E+) and absent in 15 women and 11 men (E-).

INTERVENTION

Subjects consumed a low fat (25% energy), low cholesterol (less than 200 mg/day) diet. After two weeks on this background diet (baseline) subjects were randomly assigned to consume a liquid supplement for three weeks which was either fat and cholesterol free or which contained fat (30 to 36 g) and cholesterol (650 to 780 mg). After the first three-week period subjects switched to the other supplement. Blood samples were collected for plasma lipid analysis after an overnight fast on two consecutive days at the end of baseline and on three consecutive days after each three-week supplement period.

RESULTS

There was no significant difference in response to diet between the RFLP groups. Changes in plasma total, low density lipoprotein (LDL), high density lipoprotein(HDL), HDL2 and HDL3 cholesterol or plasma triglyceride were not different between the two RFLP groups. There was a significant difference between RFLP groups for baseline HDL2-cholesterol (0.31 +/- 0.04 and 0.16 +/- 0.02 mmol/L for E- and E+ subjects, respectively) which was independent of sex and apoE genotype (P = 0.032).

CONCLUSIONS

These results indicate that the EcoRI RFLP of the apoB gene is not associated with response to dietary fat and cholesterol.

Human high molecular weight-melanoma associated antigen mimicry by mouse anti-idiotypic monoclonal antibody MK2-23: modulation of the immunogenicity in patients with malignant melanoma

The mouse anti-idiotypic (anti-id) mAb MK2-23 bears the mirror image of the antigenic determinant defined by antihuman high molecular weight-melanoma associated antigen (HMW-MAA) mAb 763.74. The purpose of this study was to evaluate the effect of conjugation to a carrier and administration with an adjuvant and cyclophosphamide (CTX) on the immunogenicity of anti-id mAb MK2-23 in patients with malignant melanoma and to analyze the relationship between development of humoral immunity and survival time of patients. Fifty-eight patients were sequentially entered into four immunization protocols which included administration of mAb MK2-23, mAb MK2-23 conjugated to keyhole limpet hemocyanin (KLH) and mixed with Bacillus Calmette-Guérin (BCG), mAb MK2-23 and CTX, and mAb MK2-23 conjugated to KLH and mixed with BCG and CTX. Six patients could not be evaluated since they withdrew from the clinical trial after the first immunization. Sera were tested for the development of anti-anti-id antibodies, including those reacting with HMW-MAA. Testing of sera for development of antimouse Ig antibodies was used to monitor the immune competence of patients. Conjugation to KLH and administration with BCG markedly enhanced the ability of mAb MK2-23 to induce anti-anti-id antibodies, including those reacting with HMW-MAA. In contrast, pretreatment with CTX had no detectable effect on the ability of mAb MK2-23 to elicit a humoral anti-anti-id response. Kaplan-Meier survival analysis showed that the performance status of patients, anti-anti-id antibody level, and development of anti-HMW-MAA antibodies had an effect on survival time. This effect was found when the survival time was calculated both from the day of the first immunization and from 4 weeks after the first immunization to the end of the study. A multivariate analysis by Cox regression showed that the development of anti-HMW-MAA antibodies was the most important variable for predicting survival, and that performance status was the only variable that significantly added to the prediction of survival. These data have to be interpreted with caution because of the retrospective nature of the analysis. Nevertheless, the present study suggests that mAb MK2-23 represents a useful immunogen to implement active, specific immunotherapy in patients with malignant melanoma.

Isoprenylation of proteins in the protozoan Giardia lamblia

We report the ability of Giardia lamblia to modify several of its cellular proteins by isoprenylation. Trophozoites cultured in the presence of [3H]mevalonate synthesized radiolabeled proteins of approx. 50 and 21-26 kDa. Chemical analysis indicated that farnesyl and geranylgeranyl isoprenoids comprised the majority of the radiolabel covalently associated with trophozoite proteins. In addition, antibodies to human p21ras immunoprecipitated mevalonate-labelled species of approx. 21 kDa. Inhibitors of several enzymatic steps of the mevalonate pathway dramatically affected Giardia metabolism. Protein isoprenylation and cell growth were blocked by compactin and mevinolin, competitive inhibitors of HMG-CoA reductase, the rate-limiting enzyme in isoprenoid biosynthesis. In the presence of these inhibitors, Giardia growth was restored by the addition of mevalonate to the culture medium. In contrast, cell growth was blocked irreversibly by inhibitors of subsequent steps in the protein isoprenylation pathway. Trophozoite growth inhibition by limonene, perillic acid, perillyl alcohol and N-acetyl-S-farnesyl-L-cysteine was not reversed after the addition of mevalonate, dolichol, ubiquinone or cholesterol to the medium. These observations constitute the first description of protein isoprenylation in any protozoan and indicate that this post-translational modification is an important step in the regulation of the growth of this primitive eukaryote.

Characterization of mevalonate-labeled lipids isolated from parasite proteins in Schistosoma mansoni

Adult paired schistosomes incubated for 3 days in radiolabeled mevalonate can effectively label at least 2 major proteins with apparent sizes of 25 and 43 kDa. The 25-kDa mevalonate-labeled proteins comigrated with proteins that could be labeled with GTP. The lipids attached to these proteins were removed and resolved by HPLC and found to comigrate with known samples of farnesol and geranylgeraniol. Homogenates of the schistosome when incubated with labeled farnesol pyrophosphate effectively labeled a protein(s) with an apparent molecular weight of 43 kDa while homogenates incubated in the presence of labeled geranylgeranyl pyrophosphate-labeled schistosome proteins with an apparent molecular weight of 25 kDa. Our results demonstrate that Schistosoma mansoni has the ability to covalently attach farnesol and geranylgeranyl to low-molecular weight proteins.

Effect of Cordyceps sinensis on erythropoiesis in mouse bone marrow

The effect of Cordyceps sinensis crystal (CS-Cr) on stimulating proliferation of erythroid progenitor cells (CFU-E and BFU-E) in LACA mouse marrow in vivo and in vitro by methyl cellulose gel culture system is reported. The numbers of CFU-E and BFU-E were increased after 5 consecutive daily treatment with 100, 150 and 200 mg/kg of CS-Cr with a peak at 150 mg/kg. Higher doses (> 150 mg/kg) of CS-Cr resulted in a reduction of the peak of CFU-E and BFU-E and then, the numbers returned to the control level with increased doses. The cytosine arabinoside (Ara-C) suicide test showed significant increases in the percentage of CFU-E and BFU-E in S-phase after CS-Cr treatment. Pretreatment of mice with CS-Cr could protect CFU-E and BFU-E against the cytotoxic agent--harringtonine. Addition of CS-Cr to culture system also promoted the generation of CFU-E and BFU-E at concentrations of 150-200 micrograms/ml in vitro. With a liquid culture technique, a stimulatory action of CS-Cr on fibroblast colony-forming units (CFU-F) proliferation was seen in vivo and in vitro.