Collective electronic excitations in the ultra violet regime in 2-D and 1-D carbon nanostructures achieved by the addition of foreign atoms

Plasmons in the visible/UV energy regime have attracted great attention, especially in nano-materials, with regards to applications in opto-electronics and light harvesting; tailored enhancement of such plasmons is of particular interest for prospects in nano-plasmonics. This work demonstrates that it is possible, by adequate doping, to create excitations in the visible/UV regime in nano-carbon materials, i.e., carbon nanotubes and graphene, with choice of suitable ad-atoms and dopants, which are introduced directly into the lattice by low energy ion implantation or added via deposition by evaporation. Investigations as to whether these excitations are of collective nature, i.e., have plasmonic character, are carried out via DFT calculations and experiment-based extraction of the dielectric function. They give evidence of collective excitation behaviour for a number of the introduced impurity species, including K, Ag, B, N, and Pd. It is furthermore demonstrated that such excitations can be concentrated at nano-features, e.g., along nano-holes in graphene through metal atoms adhering to the edges of these holes.

Ion implantation of graphene-toward IC compatible technologies

Doping of graphene via low energy ion implantation could open possibilities for fabrication of nanometer-scale patterned graphene-based devices as well as for graphene functionalization compatible with large-scale integrated semiconductor technology. Using advanced electron microscopy/spectroscopy methods, we show for the first time directly that graphene can be doped with B and N via ion implantation and that the retention is in good agreement with predictions from calculation-based literature values. Atomic resolution high-angle dark field imaging (HAADF) combined with single-atom electron energy loss (EEL) spectroscopy reveals that for sufficiently low implantation energies ions are predominantly substitutionally incorporated into the graphene lattice with a very small fraction residing in defect-related sites.

Characterization of an altered DNA topoisomerase ii-alpha from a mitoxantrone resistant Mammalian-cell line hypersensitive to DNA cross-linking agents

To further define the molecular basis for drug resistance to mitoxantrone, a Chinese hamster ovary cell line (MXN(4)) was selected in the presence of 25 nM mitoxantrone and fully characterized. This cell line is 20-fold resistant to mitoxantrone, cross-resistant to several other topoisomerase II poisons, and 2- to 3-fold collaterally sensitive to cisplatin, carboplatin and BCNU. Neither an alteration in cellular uptake of topoisomerase II inhibitor nor overexpression of P-glycoprotein contribute to the drug resistance of MXN(4) cells. Immunoblotting demonstrates equivalent amounts of topoisomerase II alpha and beta in the wild-type and drug resistant cell lines, suggesting that a quantitative alteration in topoisomerase II is not the mechanism of resistance of MXN(4) cells. Mitoxantrone-induced DNA double strand breaks measured in situ were attenuated 28-fold in the drug resistant cell line. Nuclear extracts of MXN(4) cells, as well as topoisomerase II alpha purified to homogeneity from these cells, were found to be markedly resistant to drug-induced covalent DNA: topoisomerase II complex formation. The catalytic activity of purified MXN(4) topoisomerase II was the same as wild-type activity. Thus, the resistance of MXN(4) cells to mitoxantrone involves the expression of a topoisomerase II alpha with altered DNA cleavage activity. The hypersensitivity of this cell line to platinum analogs is due to an apparent increased uptake of these drugs which results in augmented DNA interstrand crosslinking.

Search for effects beyond the born approximation in polarization transfer observables in e(over→)p elastic scattering

Intensive theoretical and experimental efforts over the past decade have aimed at explaining the discrepancy between data for the proton electric to magnetic form factor ratio, G(E)/G(M), obtained separately from cross section and polarization transfer measurements. One possible explanation for this difference is a two-photon-exchange contribution. In an effort to search for effects beyond the one-photon-exchange or Born approximation, we report measurements of polarization transfer observables in the elastic H(e[over →],e(')p[over →]) reaction for three different beam energies at a Q(2)=2.5  GeV(2), spanning a wide range of the kinematic parameter ε. The ratio R, which equals μ(p)G(E)/G(M) in the Born approximation, is found to be independent of ε at the 1.5% level. The ε dependence of the longitudinal polarization transfer component P(ℓ) shows an enhancement of (2.3±0.6)% relative to the Born approximation at large ε.

Recoil polarization measurements of the proton electromagnetic form factor ratio to Q2 = 8.5 GeV2

Among the most fundamental observables of nucleon structure, electromagnetic form factors are a crucial benchmark for modern calculations describing the strong interaction dynamics of the nucleon's quark constituents; indeed, recent proton data have attracted intense theoretical interest. In this Letter, we report new measurements of the proton electromagnetic form factor ratio using the recoil polarization method, at momentum transfers Q2=5.2, 6.7, and 8.5  GeV2. By extending the range of Q2 for which G(E)(p) is accurately determined by more than 50%, these measurements will provide significant constraints on models of nucleon structure in the nonperturbative regime.

p38 Kinase-dependent MAPKAPK-2 activation functions as 3-phosphoinositide-dependent kinase-2 for Akt in human neutrophils

Akt activation requires phosphorylation of Thr(308) and Ser(473) by 3-phosphoinositide-dependent kinase-1 and 2 (PDK1 and PDK2), respectively. While PDK1 has been cloned and sequenced, PDK2 has yet to be identified. The present study shows that phosphatidylinositol 3-kinase-dependent p38 kinase activation regulates Akt phosphorylation and activity in human neutrophils. Inhibition of p38 kinase activity with SB203580 inhibited Akt Ser(473) phosphorylation following neutrophil stimulation with formyl-methionyl-leucyl-phenylalanine, FcgammaR cross-linking, or phosphatidylinositol 3,4,5-trisphosphate. Concentration inhibition studies showed that Ser(473) phosphorylation was inhibited by 0.3 microm SB203580, while inhibition of Thr(308) phosphorylation required 10 microm SB203580. Transient transfection of HEK293 cells with adenoviruses containing constitutively active MKK3 or MKK6 resulted in activation of both p38 kinase and Akt. Immunoprecipitation and glutathione S-transferase (GST) pull-down studies showed that Akt was associated with p38 kinase, MK2, and Hsp27 in neutrophils, and Hsp27 dissociated from the complex upon activation. Active recombinant MK2 phosphorylated recombinant Akt and Akt in anti-Akt, anti-MK2, anti-p38, and anti-Hsp27 immunoprecipitates, and this was inhibited by an MK2 inhibitory peptide. We conclude that Akt exists in a signaling complex containing p38 kinase, MK2, and Hsp27 and that p38-dependent MK2 activation functions as PDK2 in human neutrophils.

Access to coronary artery bypass surgery by race/ethnicity and gender among patients who are appropriate for surgery

OBJECTIVE

The study sought to determine if there were race/ethnicity or gender differences in access to coronary artery bypass graft (CABG) surgery among patients who have been designated as appropriate and as necessary for that surgery according to the RAND methodology.

METHODS

RAND appropriateness and necessity criteria were used to identify a race/gender stratified sample of postangiography patients who would benefit from coronary artery bypass graft surgery. These patients were tracked for 3 months to determine if they had undergone coronary artery bypass graft surgery in New York State. Subjects were a total of 1,261 postangiography patients in eight New York hospitals in 1994 to 1996. Measures included percentages of patients for whom coronary artery bypass graft surgery was appropriate and necessary undergoing surgery by race/ethnicity and gender, as well as multivariate odds ratios for race/ethnicity and gender.

RESULTS

After controlling for age, payer, number of vessels diseased, and presence of left main disease, African-American and Hispanic patients were found to be significantly less likely to undergo coronary artery bypass graft surgery than white non-Hispanic patients (respective odds ratios 0.64 and 0.60). When "necessity" was used as a criterion instead of "appropriateness," significant differences in access for African-American patients remained. The gatekeeper physician recommended surgery only 10% of the time that patients did not undergo "appropriate" coronary artery bypass graft surgery, and this percentage did not vary significantly by race/ethnicity or gender of the patient.

CONCLUSIONS

Even after controlling for appropriateness and necessity for coronary artery bypass graft surgery in a prospective study, African-American patients had significant access problems in obtaining coronary artery bypass graft surgery. These problems appeared not to be related to patient refusals.

Membrane-associated carbonic anhydrase in cultured rabbit nonpigmented ciliary epithelium

PURPOSE

To measure the activity of membrane-associated carbonic anhydrase (CA) in cultured rabbit nonpigmented epithelial (NPE) cells, determine its identity and its sensitivity to extracellular trypsin, and compare the ability of acetazolamide and a cell-impermeant dextran-bound CA inhibitor to change cytoplasmic pH.

METHODS

Studies were conducted using a cell line derived from rabbit NPE. The cells were lysed and separated into soluble and insoluble fractions by differential centrifugation. CA activity in these fractions was determined using a CO2 hydration assay. In studies with intact cells, a membrane-impermeable high-molecular-weight dextran-bound inhibitor (DBI) was synthesized and used to selectively bind and inhibit the extracellular-facing membrane-bound CA. Measurements of CA activity in intact red blood cells were conducted to confirm DBI remains extracellular. Acetazolamide, a membrane-permeable CA inhibitor, was used to inhibit total CA activity. Intracellular pH was determined using the pH-dependent absorbance of the fluorescent dye BCECF-AM.

RESULTS

A low-speed pellet enriched with plasma membrane material accounted for 22.3 +/- 6.1% (n = 18) of the total CA activity in the cultured NPE. When intact cells were exposed to trypsin-EDTA, a 28% reduction of membrane-associated CA activity was observed; DBI inhibited this CA activity loss. Cytosolic CA activity was inhibited by 0.2% sodium dodecyl sulfate (SDS). In contrast, membrane-associated CA was SDS resistant, a characteristic of the CA-IV isozyme. By Western blot, CA-IV immunoreactive polypeptide was detected in the cultured cells and also in native rabbit and porcine ciliary epithelium. Inhibition of total CA activity with acetazolamide and inhibition of extracellular-facing membrane-associated CA with DBI caused an identical intracellular pH decrease in intact NPE cells.

CONCLUSIONS

Expression of the CA-IV isozyme could account for the significant fraction of CA activity in the cultured NPE, which is membrane associated and SDS resistant. Sensitivity to tryptic hydrolysis suggests the membrane-associated CA partially faces extracellularly. As judged by responses to an extracellular CA inhibitor, the membrane-associated CA has a functional role in maintaining cytoplasmic pH.

The in vitro effects of interleukin-12 upon tumor-infiltrating lymphocytes derived from renal cell carcinoma

Clinical trials utilising interleukin (IL)-2 with tumor-infiltrating lymphocytes (TIL) have demonstrated efficacy in the treatment of metastatic renal cell carcinoma (RCC). Several cytokines, as well as growth factors have demonstrated modulatory effects upon the biological properties of TIL from RCC, suggesting a potentially important role for cytokines other than IL-2 in the development of active and tumor-specific TIL. IL-12 was recently characterized as a natural-killer-cell-stimulatory factor or cytotoxic-T-cell-maturation factor. These properties of IL-12 prompted us to investigate the impact of this cytokine upon the activation of TIL from human RCC. In an attempt to enhance the in vitro growth and activity of renal TIL, we have grown eight renal TIL cultures in varying concentrations of IL-2 (8, 40, 80, 400 U/ml) and IL-12 (200 U/ml). In addition, IL-12 (200 U/ml) was added to TIL cultures pre-activated with IL-2 (400 U/ml). Growth, cell expansion, and the ability of TIL to release certain cytokines upon tumor stimulation were determined. Proliferation assays, phenotypic analysis, and cytotoxicity assays were performed at an early and a late culture stage. IL-12, alone and when added to suboptimal concentrations of IL-2, failed to induce TIL growth. While the addition of IL-12 to optimal doses of IL-2 suppressed TIL culture expansion, sequential culture exposure first to IL-2 and then to IL-2+IL-12 increased the number of cells expressing CD3+/CD56+ and these cultures demonstrated enhanced in vitro lysis of autologous tumor. IL-12 clearly demonstrated a sequence-dependent impact of the biological behaviour of TIL from RCC. The optimal use of IL-12 in the in vitro expansion of renal TIL may result in cells with an enhanced specific anti-tumor effect.

Natural immune reactivity-associated therapeutic response in patients with metastatic renal cell carcinoma receiving tumor-infiltrating lymphocytes and interleukin-2-based therapy

Combination therapy with systemically administered interleukin-2 (IL-2) and tumor infiltrating lymphocytes (TIL) demonstrates significant clinical activity in some patients with metastatic renal cell carcinoma (RCC). The objective of this study was to identify predictors of therapeutic response in patients with IL-2- and TIL-based immunotherapy. We characterized and compared immunologic properties of tumors, TILs, peripheral blood lymphocytes (PBLs) and sera of responding (R, n = 8) with nonresponding patients (NR, n = 9). Before undergoing nephrectomy, responding patients exhibited a higher percentage of circulating natural killer (NK) cells (CD56+ CD3-) (43 +/- 20%) as compared with nonresponders (18 +/- 16%) (p < 0.01). After nephrectomy, the CD56+ CD3-/CD56- CD3+ ratio in responding patients (pre: 2.60 +/- 2.24; post: 0.28 +/- 0.19; p < 0.05) significantly decreased and was similar to that of patients not responding to therapy (0.42 +/- 0.36). Sera from patients responding to immunotherapy, obtained before and after completion of therapy, contained natural killer (NK)-enhancing factor(s) that significantly enhanced the proliferation (3.2 x 10(3) +/- 25%/ 3.6 x 10(3) +/- 13% counts/min) and cytotoxicity [17.6 +/- 4.0/18.0 +/- 1.9 lytic units (LU)] of fresh PBLs as compared with normal serum (1.8 x 10(3) +/- 8% counts/min; 13.4 +/- 2.5 LU) or sera from nonresponders (1.6 x 10(3) +/- 25%/1.5 x 10(3) +/- 20% counts/min; 8.3 +/- 5.9/6.8 +/- 4.8 LU). In contrast to noncultured tumor suspension, IL-2 cultivation induced TIL growth, cytotoxicity, and multicytokine synthesis, and a complete clearance of tumor cells. No significant differences were observed between responders and nonresponders in the in vitro characteristics of tumor/TIL, which include the degree of intratumoral lymphocytic infiltrate, TIL expansion, specific lysis of autologous tumor, phenotype, expansion time, quantity of TIL infused, cytokine release, and degree of tumor aggressiveness. We conclude that clinical response to TIL and IL-2-based immunotherapy is associated with patients' baseline natural immune status. The percentage of circulating NK cells and the presence of serum NK-cell-enhancing factors may serve as potential predictors of response in patients with advanced RCC. The in vitro study of RCC-TIL suggests that activated TIL may provide a synergistic effect to that of administered IL-2 on activation of cellular immune response in situ, rendering a tumor eradication, while the clinical outcome is largely dependent on the pretreatment immune status of patient.

Management of disseminated kidney cancer

The approach to disseminate renal cell carcinoma (RCC) has evolved significantly in recent years, largely owing to the progress of biologic therapy development. With increasing knowledge of biologic therapy come several dilemmas, including the choice of cytokine therapy, the appropriate mode of delivery, the selection of candidates for given therapeutic options, and the role of cytoreductive nephrectomy in immunotherapy protocols. This article reviews the historical development of immunotherapy and the lessons learned from previous experience and offers a logical approach to the patient with disseminated RCC.

Interferon-alpha primed tumor-infiltrating lymphocytes combined with interleukin-2 and interferon-alpha as therapy for metastatic renal cell carcinoma

Murine models demonstrate therapeutic synergy for the combination of interleukin-2, interferon-alpha and tumor-infiltrating lymphocytes. We treated 11 patients with metastatic renal cell carcinoma with a novel regimen consisting of in vivo primed tumor-infiltrating lymphocytes, interferon-alpha and interleukin-2. Patients received interferon-alpha before radical nephrectomy; in vivo primed tumor-infiltrating lymphocytes were isolated and expanded in vitro. Low dose continuous infusion interleukin-2 at a dose of 2 x 10(6) units per m.2 per day was administered for 96 hours during each treatment week and interferon-alpha was administered as a subcutaneous injection at a dose of 6 x 10(6) units per m.2 per day on days 1 and 4 of the interleukin-2 infusion. No therapy was given during the last 3 days of a treatment week. One course of therapy consisted of 3 weeks of therapy followed by 3 weeks of rest. Patients were treated until maximal response, disease progression or dose limiting toxicity. A maximum of 6 courses of therapy were administered. Eleven patients underwent interferon-alpha priming and subsequent radical nephrectomy. In vivo primed tumor-infiltrating lymphocytes were successfully expanded in all 11 patients with an expansion index of greater than 170. In vivo primed tumor-infiltrating lymphocytes maintained their lytic activity for greater than 5 to 8 weeks in culture as demonstrated in the 4-hour 51chromium release assay. Ten patients underwent multimodality biological therapy and 3 (30%, 95% confidence interval 6 to 65%) have achieved complete response (2 clinical and 1 surgical) with durations of 24+, 23+ and 5+ months. Patients with stable disease received no additional therapy. No deaths and no grade 4 toxicities occurred. Immunotherapy using a combination of interferon-alpha primed tumor-infiltrating lymphocytes, low dose continuous infusion interleukin-2 and interferon-alpha can induce significant and durable antitumor responses in some patients with advanced renal cell carcinoma.

Soluble tumor necrosis factor receptor expression in patients with metastatic renal cell carcinoma treated with interleukin-2-based immunotherapy

Two distinct types of soluble tumor necrosis factor alpha receptors (sTNFRs), which are felt to represent proteolytic cleavage products of the extracellular domains of membrane-bound TNFRs of molecular mass, 55 and 75 kDa, are found in the serum and urine of humans. We have measured the serum concentrations of these receptors in eight patients with metastatic renal cell carcinoma during treatment with interleukin-2 (IL-2)-based immunotherapy. The mean pretreatment concentration of sTNFR-55 kDa (p < 0.05) but not sTNFR-75 kDa was significantly elevated prior to the onset of immunotherapy. In one patient the concentrations of both sTNFRs decreased dramatically following removal of the primary tumor. There were significant increases in the concentrations of both sTNFRs in patients treated with IL-2-based therapy that included in vivo primed tumor infiltrating lymphocytes (pTILs); some of these patients eventually achieved a complete response to therapy. These data demonstrate that sTNFR-55 kDa is elevated in patients with metastatic renal cell carcinoma prior to therapy and that IL-2-based therapy that included pTIL cells results in a further increase in sTNFRs.

Hemostatic evaluation of Sarns/3M-VAD implantation in calves

The authors evaluated the potential for thrombotic complications arising from implantation of a ventricular assist device (Sarns/3M-VAD) in four calves. Coagulation screening tests (prothrombin time [PT], partial thromboplastin time [PTT], thrombin time [TT]), fibrinogen levels, and antithrombin III functional activity were found to be of little value as predictors of the degree of activation of the hemostatic system. However, platelet counts, adenosine diphosphate (ADP)- and collagen-induced platelet aggregation, and thromboxane (TXB2) levels were good indicators of changes in platelet reactivity. Platelet counts (initial value 6 x 10(5) rose, and were associated with increased rate and extent of ADP- and collagen-induced platelet aggregation, which remained elevated during the entire 25 day postimplantation period. The first 5 days postimplantation revealed a typical acute inflammatory response, with increased platelet levels, but with TXB2 levels significantly decreased during this period. A monoclonal antibody based bovine D-dimer assay and Western blot studies indicated a small but significant increase in circulating bovine D-dimer, indicating localized fibrin formation and its dissolution.

A completely implantable total artificial heart system

The authors developed, built, and tested in vivo a completely implanted total artificial heart (TAH) system. The system used a reduced size version of a roller screw energy converter and mating sac blood pumps. The motor drive, pumps, and a compliance chamber were implanted intrathoracically. A canister containing controlling electronics and an emergency battery was implanted in the abdomen. The secondary coil of an inductive energy transmission and telemetry system was placed over the ribs. The system was implanted in three calves, that survived 0.5-13 days with the system. The system maintained safe left atrial pressures and adequate cardiac outputs during each animal's entire course.

Hematologic abnormalities and thromboembolic complications in calves implanted with pneumatic artificial hearts. Long-term studies and autopsy findings

The purpose of this study was to assess hematologic abnormalities and thromboembolic complications related to long-term use of the pneumatic artificial heart (PAH). Laboratory data and autopsy findings were analyzed from 24 calves that survived 70-353 (150 +/- 82) days after implantation of a PAH. Compared with baseline levels, the hemoglobin was significantly lower, and the plasma hemoglobin and serum LDH significantly higher, throughout the follow-up period. The platelet count decreased during the first 10-30 weeks, but returned to preoperative levels by week 35. Platelet survival in 4 calves in stable condition was normal, and the leukocyte count and absolute neutrophil count were within normal limits. At autopsy, thrombotic complications and organ infarction were noted in 13 calves, and major septic complications were documented in 10 animals. The authors' observations indicate that thromboembolism and infection are major complications of long-term use of the PAH.

Effect of coumadin-induced coagulopoietin plasma on vitamin K-dependent carboxylation of liver microsomes

Coumadin-treated rabbits have a humoral substance(s) (coagulopoietin) which is capable of elevating vitamin K-dependent coagulation factors when injected into recipient rabbits (Karpatkin & Karpatkin, 1973). Biologic levels of coagulation factors II, V, VII and X; immunologic levels of factors II and X; and vitamin K-dependent liver microsomal carboxylase activity were measured in recipient rabbits receiving coumadin-induced coagulopoietin plasma. Factor II biologic activity increased 3.5-fold compared to the increase in immunologic activity. Factor X biologic activity increased 1.7-fold compared to the increase in immunologic activity. This indicates an increase in specific activity of factors II and X. Coumadin-induced coagulopoietin plasma had no effect on vitamin K-dependent liver microsomal carboxylase activity in vitro. However, livers obtained from recipient animals treated with coumadin-induced coagulopoietin plasma enhanced their carboxylase activity (compared to control animals) 2.4-fold employing endogenous microsomal precursor for carboxylation, and 6.2-fold employing synthetic substrate, phe-leu-glu-glu-val. Thus, coumadin-induced coagulopoietin plasma enhances the biologic activity of vitamin K-dependent coagulation factors II, VII, and X as well as the ex vivo vitamin K-dependent carboxylase activity of liver microsomes.

Surgical history of Crohn's disease in a well-defined population

Since 1935, 42 of 103 residents of Olmsted County, Minnesota, identified as having Crohn's disease underwent one or more surgical procedures. The incidence and type of surgical intervention, distribution of disease, and risk of recurrent disease after surgery were analyzed. Follow-up extended to 32 years, with a median of 8.5 years. Thirty-six patients underwent at least one definitive resection; eight of these patients subsequently underwent a second definitive operation. The likelihood that any patient would undergo operation was greatest within the first year of diagnosis. The proportion of patients in whom recurrent disease developed after the first and second definitive resections was 50% and 37%, respectively. Approximately half the patients who experienced a recurrence underwent further surgery. The site of diseased bowel and sex were not factors specifically influencing recurrence rates. Patients 40 years of age and older who underwent surgery appeared to fare better with respect to recurrent disease than younger patients. Although our findings suggest cumulative risks of recurrent disease after definitive resection similar to those reported from larger population groups or major referral centers, the proportion of patients who underwent surgery during the natural history of their Crohn's disease was much less than generally reported. We conclude that operation for Crohn's disease is not inevitable and that evidence to the contrary may imply both a treatment and a referral bias.

Fourier analysis of covert speech behavior. A progress report

Frequency characteristics of electromyographic traces from the tongue and lips were studied as a function of class of phonemic input. Previous research has established that there are amplitude increases in the lips while processing bilabial linguistic units such as [p] and in the tongue when processing lingual-alveolar units (like [t]). Preliminary results using variability measures suggest similar conclusions for frequency parameters.