Wafer-Scale Carbon Nanotubes Diodes Based on Dielectric-Induced Electrostatic Doping

Diodes based on p-n junctions are fundamental building blocks for numerous circuits, including rectifiers, photovoltaic cells, light-emitting diodes (LEDs), and photodetectors. However, conventional doping techniques to form p- or n-type semiconductors introduce impurities that lead to Coulomb scattering. When it comes to low-dimensional materials, controllable and stable doping is challenging due to the feature of atomic thickness. Here, by selectively depositing dielectric layers of Y2O3 and AlN, direct formation of wafer-scale carbon-nanotube (CNT) diodes are demonstrated with high yield and spatial controllability. It is found that the oxygen interstitials in Y2O3, and the oxygen vacancy together with Al-Al bond in AlN/Y2O3 electrostatically modulate the intrinsic CNTs channel, which leads to p- and n-type conductance, respectively. These CNTs diodes exhibit a high rectification ratio (>104) and gate-tunable rectification behavior. Based on these results, we demonstrate the applicability of the diodes in electrostatic discharge (ESD) protection and photodetection.

Quality of Split-Mouth Trials in Dentistry: 1998, 2008, and 2018

The objectives of this study were to assess the reporting quality and methodological quality of split-mouth trials (SMTs) published during the past 2 decades and to determine whether there has been an improvement in their quality over time. We searched the MEDLINE database via PubMed to identify SMTs published in 1998, 2008, and 2018. For each included SMT, we used the CONsolidated Standards Of Reporting Trials (CONSORT) 2010 guideline, CONSORT for within-person trial (WPT) extension, and a new 3-item checklist to assess its trial reporting quality (TRQ), WPT-specific reporting quality (WRQ), and SMT-specific methodological quality (SMQ), respectively. Multivariable generalized linear models were performed to analyze the quality of SMTs over time, adjusting for potential confounding factors. A total of 119 SMTs were included. The mean overall score for the TRQ (score range, 0 to 32), WRQ (0 to 15), and SMQ (0 to 3) was 15.77 (SD 4.51), 6.06 (2.06), and 1.12 (0.70), respectively. The primary outcome was clearly defined in only 28 SMTs (23.5%), and only 27 (22.7%) presented a replicable sample size calculation. Only 45 SMTs (37.8%) provided the rationale for using a split-mouth design. The correlation between body sites was reported in only 5 studies (4.2%) for sample size calculation and 4 studies (3.4%) for statistical results. Only 2 studies (1.7%) performed an appropriate sample size calculation, and 46 (38.7%) chose appropriate statistical methods, both accounting for the correlation among treatment groups and the clustering/multiplicity of measurements within an individual. Results of regression analyses suggested that the TRQ of SMTs improved significantly with time ( P < 0.001), while there was no evidence of improvement in WRQ or SMQ. Both the reporting quality and methodological quality of SMTs still have much room for improvement. Concerted efforts are needed to improve the execution and reporting of SMTs.

Prevalence and Risk Factors Governing the Loss of Muscle Function in Elderly Sarcopenia Patients: A longitudinal Study in China with 4 Years of Follow-Up

OBJECTIVES

Data regarding the occurrence of risk factors that promote the loss of muscle mass, strength and function in sarcopenia patients in elderly Chinese patients are sparse. Here, we investigated the alterations in muscle mass, function and strength in those with sarcopenia over a 4-year period. We further evaluated the risk factors leading to a loss of grip strength, gait speed and skeletal muscle mass index in sarcopenia patients.

DESIGN

A face-to-face cross-sectional survey.

SETTING AND PARTICIPANTS

The study population consisted of 560 Chinese aged over 59 years.

MEASUREMENTS

Study recordings took places over a four-year period from 2014. Muscle mass was assessed through bioelectrical impedance analysis (BIA) performed on an Inbody720, Biospace. Hand-grip strength and 6 m walking speed were used as measurements of muscle strength and function. Sarcopenia was diagnosed using the Asian Working Group for Sarcopenia criteria (AWGS).

RESULTS

In total, 474 of the elderly residents completed the follow-up. The rates of decreased ASMI, grip strength, and gait speed in the sarcopenia patients increased over the 4-year period. Following multivariate analysis, age was identified as the main risk factor for all the observed decrease, gender was specifically related to the loss of ASMI, stroke was a risk factor for gait speed and sarcopenia. A high BMI was a risk factor for a low gait speed but was protective for a loss of skeletal muscle mass and sarcopenia.

CONCLUSIONS

Age leads to a decline in muscle strength and function. In elderly Chinese patients with sarcopenia, the rates of reduced grip strength, gait-speed and sarcopenia increased. A high BMI was protective against the decline in muscle mass and sarcopenia, but represented a risk factor for low gait speed. Stoke was identified to cause a loss of gait speed in sarcopenia patients.

[Effect of NLRP3 mediated pyroptosis in myocardial cells undergoing hypoxia/deoxygenation injury]

Objective: To investigate the effect of NACHT-LRR-PYD- containing proteins 3 (NLRP3) mediated pyroptosis in myocardial cells undergoing hypoxia/deoxygenation (H/R) injury. Methods: In order to observe whether H/R-treatment could cause pyroptosis, H9c2 cells were divided into 2 groups randomly using the lottery method: control group(without H/R-treatment) and H/R group (in which the H9c2 cells were underwent H/R-treatment). In order to clarify the role of pyroptosis in H/R-injury, H9c2 cells were divided into 4 groups randomly using the lottery method: control group(in which the H9c2 cells were cultivated with normal medium); YVAD group(in which the H9c2 cells were pretreated with z-Val-Ala-Asp(Ome)-fluoromethylketone (Z-YVAD-FMK) 20 μm for 4 hours, then replaced with normal medium); H/R group(H9c2 cells underwent H/R-treatment); YVAD+H/R group (in which the H9c2 cells were pretreated with 20 μm Z-YVAD-FMK for 4 hours before H/R-treatment). To determine whether H/R-induced cell pyroptosis is associated with NLRP3, H9c2 cells were divided into 4 groups randomly using the lottery method: control group (in which cells were transfected with a control nonspecific siRNA); si-NLRP3 group (in which cells were transfected with NLRP3-targeting siRNA); H/R group(in which cells were transfected with a control nonspecific siRNA before H/R-treatment); si-NLRP3+H/R group(in which the H9c2 cells were transfected with NLRP3-targeting siRNA before H/R-treatment). Pore formation on cell membrane was detected by propidium iodide (PI) staining. Cell viability was detected by CCK8 reagent. The protein expression of Caspase-1, interleukin-1β (IL-1β) and NLRP3 was detected by Western blot. Results: (1) The positive rate of PI staining ((26.46±5.15)% vs. (1.69±0.73)%,P<0.01), expression of NLRP3 (0.57±0.16 vs. 0.23±0.06,P<0.01), expression of Caspase-1 (1.07±0.13 vs. 0.37±0.08,P<0.01), and expression of IL-1β (0.38±0.08 vs. 0.16±0.05,P<0.01) were significantly higher in H/R group than in control group. (2)The cell vitality was significantly higher in YVAD+H/R group than in H/R group ((87.31±9.05)% vs. (73.30±7.19)%, P<0.05).The positive rate of PI staining was significantly decreased in YVAD+H/R group than in H/R group ((18.12±4.36)% vs. (26.45±4.60)%, P<0.05). The expression of Caspase-1 (0.72±0.12 vs. 1.07±0.15, P<0.05) and IL-1β(0.29±0.07 vs. 0.39±0.06, P<0.05) were significantly lower in YVAD+H/R group than in H/R group. (3) The cell vitality was significantly increased in si-NLRP3+H/R group than in H/R group ((85.46±7.71)% vs. (72.41±5.53)%, P<0.05). The positive rate of PI staining was significantly lower in si-NLRP3+H/R group than in H/R group ((18.22±4.20)% vs. (26.73±3.26)%, P<0.05). The expression of Caspase-1(0.87±0.07 vs. 1.15±0.15, P<0.05) and IL-1β(0.41±0.07 vs. 0.58±0.10, P<0.05) were significantly decreased in si-NLRP3+H/R group than in H/R group. Conclusion: NLRP3 mediated pyroptosis is involved in H/R injury of myocardial cells.

Systemic disruption of the homeostasis of transfer RNA isopentenyltransferase causes growth and development abnormalities in Bombyx mori

Isopentenylation at A37 (i⁶ A37) of some transfer RNAs (tRNAs) plays a vital role in regulating the efficiency and fidelity of protein synthesis. However, whether insects, which are well known for their highly efficient protein synthesis machinery, employ this regulatory mechanism remains uninvestigated. In the current study, a candidate tRNA isopentenyltransferase (IPT) gene with three alternative splicing isoforms (BmIPT1-BmIPT3) was identified in Bombyx mori (silkworm). Only BmIPT1 could complement a yeast mutant lacking tRNA IPT. Phylogenetic analysis showed that silkworm tRNA IPT is conserved in the Lepidoptera. BmIPT was expressed in all B. mori tissues and organs that were investigated, but was expressed at a significantly higher level in silk glands of the fourth instar compared to the first day of the fifth instar. Interestingly, BmIPT was expressed at a significantly higher level in the domesticated silkworm, B. mori, than in wild Bombyx mandarina in multiple tissues and organs. Knock-down of BmIPT by RNA interference caused severe abnormalities in silk spinning and metamorphosis. Constitutive overexpression of BmIPT1 using a cytoplasmic actin 4 promoter in B. mori raised its messenger RNA level more than sixfold compared with nontransgenic insects and led to significant decreases in the body weight and cocoon shell ratio. Together, these results confirm the first functional tRNA IPT in insects and show that a suitable expression level of tRNA IPT is vital for silk spinning, normal growth, and metamorphosis. Thus, i⁶ A modification at position A37 in tRNA probably plays an important role in B. mori protein synthesis.

Does audiovisual distraction reduce dental anxiety in children under local anesthesia? A systematic review and meta-analysis

OBJECTIVES

To perform a systematic review and meta-analysis on the effects of audiovisual distraction on reducing dental anxiety in children during dental treatment under local anesthesia.

METHODS

The authors identified eligible reports published through August 2017 by searching PubMed, EMBASE, and Cochrane Central Register of Controlled Trials. Clinical trials that reported the effects of audiovisual distraction on children's physiological measures, self-reports, and behavior rating scales during dental treatment met the minimum inclusion requirements. The authors extracted data and performed a meta-analysis of appropriate articles.

RESULTS

Nine eligible trials were included and qualitatively analyzed; some of these trials were also quantitatively analyzed. Among the physiological measures, heart rate or pulse rate was significantly lower (p = .01) in children subjected to audiovisual distraction during dental treatment under local anesthesia than in those who were not; a significant difference in oxygen saturation was not observed. The majority of the studies using self-reports and behavior rating scales suggested that audiovisual distraction was beneficial in reducing anxiety perception and improving children's cooperation during dental treatment.

CONCLUSION

The audiovisual distraction approach effectively reduces dental anxiety among children. Therefore, we suggest the use of audiovisual distraction when children need dental treatment under local anesthesia.

Metabolites from the co-culture of nigranoic acid and Umbelopsis dimorpha SWUKD3.1410, an endophytic fungus from Kadsura angustifolia

The ability of the endophytic fungus Umbelopsis dimorpha SWUKD3.1410 to transform the triterpene nigranoic acid (3, 4-secocycloarta-4(28), 24-(Z)-diene-3, 26-dioic acid; 1) was investigated. Co-culture of nigranoic acid with U. dimorpha SWUKD3.1410 yielded six major products, including a new triterpene (2) and 5 known compounds (3-7). Their structures were identified by the extensive 1D, 2D NMR and HR-ESI-MS Data analysis, and by comparison with those reported data. Among them, 2-4 were transformed from nigranoic acid (1), while 5-7 were derived from the culture medium stimulated by the substrate. On the basis of the structures of 2-4, it was proposed that the transformative process probably involved isomerase and hydroxylase, in which the former was rare in fungi. Additionally, all the compounds (1-7) were evaluated for their cytotoxic activity. As a result, compounds 1, 3-5 exhibited weak cytotoxicity against the tested cell lines, while others showed no cytotoxicity.

Roles of nicotinic acetylcholine receptors in stem cell survival/apoptosis, proliferation and differentiation

The potential of stem cells in regenerative medicine, developmental biology, and drug discovery has been well documented. For example, stem cells have the extraordinary ability of self-renewal, and also give rise to many specialized cells. It is clear that stem cell technology has revolutionized our understanding of modern biology and medicine and provided new insights into the mechanisms controlling basic cell biology and various diseases. Nicotinic acetylcholine receptors (nAChRs) are prototypical members of the ligand-gated ion channel super family of neurotransmitter receptors that play many critical roles in brain and body function. It has been demonstrated that in addition to mediation of classical excitatory neurotransmission at some loci and modulation of release of neurotransmitters in some cases, nAChRs also play important roles in influencing synaptic architecture and plasticity as well as neuronal survival/death. Recently, emerging lines of evidence have suggested that nAChRs express on stem cells, where they likely mediate crucial effects of cholinergic signaling on stem cell survival/apoptosis, proliferation, differentiation and maturation. In this review, we summarize current development in cholinergic modulations of stem cell survival/apoptosis, proliferation and differentiation in order to evaluate the impact of nAChRs in stem cell biology and pathology.

Synergy between Kaposi's sarcoma-associated herpesvirus (KSHV) vIL-6 and HIV-1 Nef protein in promotion of angiogenesis and oncogenesis: role of the AKT signaling pathway

Kaposi's sarcoma-associated herpesvirus (KSHV) is the cause of Kaposi's sarcoma (KS), which is the most common AIDS-associated malignancy. KS is characterized by neovascularization and spindle cell proliferation. The interaction between HIV-1 and KSHV has a central role in promoting the aggressive manifestations of KS in AIDS patients; however, the pathogenesis underlying AIDS-related KS (AIDS-KS) remains unknown. Herein, we examined the potential of HIV-1 negative factor (Nef) to impact KSHV viral interleukin-6 (vIL-6)-induced angiogenesis and tumorigenesis. In vitro experiments showed that exogenous Nef penetrated vIL-6-expressing endothelial cells. Both internalized and ectopic expression of Nef in endothelial cells and fibroblasts synergized with vIL-6 to promote vascular tube formation and cell proliferation. Using a chicken chorioallantoic membrane (CAM) model, we demonstrated that Nef synergistically promotes vIL-6-induced angiogenesis and tumorigenesis. Animal experiments further showed that Nef facilitates vIL-6-induced angiogenesis and tumor formation in athymic nu/nu mice. Mechanistic studies indicated that Nef synergizes with vIL-6 to enhance angiogenesis and tumorigenesis by activating the AKT pathway in the CAM model, as well as nude mice. LY294002, a specific inhibitor of phosphatidylinositol-3-kinase (PI3K), significantly impaired the ability of Nef to promote vIL-6-induced tumorigenesis in an allograft model of nude mice. Our data provide first-line evidence that Nef may contribute to the pathogenesis underlying AIDS-KS in synergy with vIL-6. These novel findings also suggest that targeting the PI3K/AKT signal may be a potentially effective therapeutic approach in AIDS-KS patients.

In situ synthesis and characterization of GaN nanorods through thermal decomposition of pre-grown GaN films

Herein we describe a thermal treatment route to synthesize gallium nitride (GaN) nanorods. In this method, GaN nanorods were synthesized by thermal treatment of GaN films at a temperature of 800 °C. The morphology and structure of GaN nanorods were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that GaN nanorods have a hexagonal wurtzite structure with diameters ranging from 30 to 50 nm. Additionally, GaN nanoplates are also founded in the products. The growth process of GaN nanostructures was investigated and a thermal decomposition mechanism was proposed. Our method provides a cost-effective route to fabricate GaN nanorods, which will benefit the fabrication of one-dimensional nanomaterials and device applications.

Identification of B cell epitopes at the C-terminus of latency-associated nuclear protein of the kaposi's sarcoma-associated herpesvirus

The latency-associated nuclear antigen (LANA) of Kaposi's sarcoma-associated herpesvirus (KSHV) plays a key role in the induction of cell transformation, maintenance of viral episome, and modulation of immune response in human. To identify the presence of B cell epitopes within C-terminus of LANA and to characterize the monoclonal antibodies (MAbs) against this protein, we expressed the C-terminal region at aa 794-1000 of LANA (pLANA-C) in Escherichia coli as a fusion protein. KSHV-positive human sera were able to recognize the recombinant LANA-C in the Western blot analysis and ELISA. Mapping of antigenic epitopes of pLANA-C by KSHV-positive human sera revealed two B cell antigenic epitopes located at aa 846-854 and aa 794-822. The MAb 3F11 recognized a region between at aa 840 to 846 of LANA and exhibited a strong and specific binding to both pLANA-C and native viral LANA. These findings showed that pLANA-C and MAb 3F11 could be used for the detection of KSHV antibodies in human sera and for the advanced study of biological functions of LANA.

Screening of upper digestive tract cancer with dilute hydrochloric acid and alcohol in a Chinese high-risk population--a follow-up study of 12 years

This is a 12-year follow-up study on screening with a mixture of 2% hydrochloric acid and 18% alcohol for upper digestive tract cancer in a Chinese high-risk population. A public screening for upper digestive tract cancer was conducted from November 1979 to May 1984 by giving a mixture of 2% hydrochloric acid and 18% alcohol to 7280 subjects in high-risk population in Yaocun village, Linxian County, Henan province. The subjects were given 15 ml of this mixture in the morning or at noon before lunch when fasting. Five minutes later, irritative reactions (retrosternal discomfort, warmth, pain or pyrosis) was felt in subjects suffering from oesophageal cancer, oesophagitis, gastritis, mucosal dysplasia or ulcer (positive group). Those with normal oesophageal or gastric mucosa felt nothing (negative group). The overall positive rate was 23.2% (1689/7280). In oesophageal or gastric cancer subjects, the positive rate of these symptoms was 88.7%. In subjects with mucosal dysplasia, it was 71.2%. A total of 26 upper digestive tract cancer patients were found. As a result of 12 years' follow-up, 271 persons with upper digestive tract cancer among the 1689 positive group subjects have been discovered, giving an annual morbidity rate of 1.34%. Among the 5591 negative group subjects, 136 persons have been found to suffer from this cancer, giving an annual morbidity rate of 0.2%. This illustrated that the annual morbidity rate of upper digestive tract cancer in the positive group was 6.65 times of that of the negative group ( <0.0001). In conclusion, screening of upper digestive tract cancer with dilute hydrochloric acid in alcohol is simple, safe, non-traumatic, effective and readily acceptable in a high-risk area in China. It may be feasible in other parts of the world, especially the developing countries.

[A limonoid from the Chinese drug dong-feng-jie (Atalantia buxifolia)]

A new limonoid was isolated from the ethanol extract of dried roots and stems of Atalantia buxifolia (Poir) Oliv.. Based on chemical properties and spectral analysis, including 1H- and 13CNMR, DEPT, MS, IR and UV spectra, its structure have been identified as: 6-deoxy-6 alpha-acetoxyatalantin acetate. This compound was isolated from this plant for the first time.

Improved efficacy of chemotherapy for glioblastoma by radiation-induced opening of blood-brain barrier: clinical results

PURPOSE

To improve the efficacy of chemotherapy for glioblastoma through the radiation-induced opening of the blood-brain barrier (BBB).

METHODS AND MATERIALS

In two previous articles, we have described the results of brain scanning using technetium 99m-labeled somatostatin and the measurement of methotrexate (MTX) concentrations in blood and cerebrospinal fluid (CSF) after i.v. injection. We discovered that the BBB and blood-cerebrospinal fluid barrier opened to a certain extent after 20- to 40-Gy irradiation, thus increasing the degree to which MTX permeated the brain tissue. On the basis of these findings, we retrospectively analyzed the outcome in 56 patients with glioblastoma given either chemotherapy (CCNU) after 20- to 40-Gy irradiation (28 patients) or radiation therapy alone (28 patients).

RESULTS

The 1-, 3-, and 5-year survival rates were 57.14%, 22.50%, and 15.00% in the combined-therapy group and 17.86%, 7.14%, and 3.57% in the radiotherapy alone group, respectively. The respective median survival times were 29.11 +/- 6.99 and 9.86 +/- 3.45 months (p < 0.001), which represented a statistically significant difference.

CONCLUSION

Our study further confirms that opening of the BBB induced by irradiation with 20-40 Gy may optimize the effects of intracranial chemotherapy.

Spatial alterations of Kv channels expression and K(+) currents in post-MI remodeled rat heart

OBJECTIVE

The hypothesis being tested in the present study is that increased anisotropic properties occurs in the remodeled post-infarction heart due to spatial alterations in Kv channels expression and K(+) currents of the remodeled myocardium.

METHODS

Three to 4 weeks post myocardial infarction (MI) in the rat, we measured the two components of the outward K(+) current, I(to-fast (f)) and I(to-slow(s)) in the epicardium (epi) and endocardium (endo) of noninfarcted remodeled left ventricle (LV) using patch clamp techniques. Alterations in mRNA and/or protein levels of potassium channel genes Kv1.4, Kv1.5, Kv2.1, Kv4.2 and Kv4.3 were measured in epi, midmyocardium (mid), and endo regions of LV and in the right ventricle (RV).

RESULTS

In sham operated rat heart, the density of I(to-f) was 2.3 times greater in epi compared to endo myocytes. In post-MI heart, the density of I(to-f) and I(to-s) decreased to a similar degree in LV epi and endo but the difference in I(to-f) density between epi and endo persisted. The mRNA and/or protein levels of Kv1.4, Kv2.1, Kv4.2 and Kv4.3 but not Kv1.5 decreased to a varying extent in different regions of LV but not in RV of post-MI heart.

CONCLUSIONS

Our results suggest that regional downregulation of Kv channels expression and density of K(+) currents can be a significant determinant of increased spatial electrophysiological heterogeneity and contribute to increased electrical instability of the post-MI heart.

Synchronization of separation and determination based on multichannel mode-filtered light detection with capillary electrophoresis

A novel method for the synchronization of separation and determination is described, in which a mode-filtered light detector is used as an online detector in capillary electrophoresis. An instrument is described which has been developed for this purpose. The round capillary used in conventional capillary electrophoresis is replaced by an annular column, which is constructed from a naked optical fibre inserted into a fused-silica capillary. In fact, the annular electrophoresis column itself forms part of the mode-filtered light sensor. Along the side of the annular column are several detection channels for gathering and transmitting the mode-filtered light to a charge-coupled device (CCD). Every channel provides information on the sample from the point at which it is located. Using capillary isotachophoresis incorporating the annular column, the analytes in a sample containing alanine (10.0 mM) and glycine (9.7 mM) were simultaneously separated and determined using multichannel mode-filtered light detection with a detection limit of 1.5 mM.

Capsaicin inhibits Jurkat T-cell activation by blocking calcium entry current I(CRAC)

Capacitative calcium entry (CCE) through stores-operated Ca2+ channels is an absolute requirement for normal activation of T lymphocytes. Organic blockers/inhibitors of the channel(s) that carry the inward Ca2+ current (I(CRAC)) responsible for CCE are few. Here we show that capsaicin, the pungent ingredient of hot chili pepper, blocks receptor-stimulated Ca2+ entry in Jurkat T cells. Indo-1 measurements of intracellular calcium show that capsaicin blocks CCE without affecting release of inositol-1,4,5-trisphosphate-sensitive internal Ca2+ stores with an IC50 of 32 microM. Block of Ca2+ entry by capsaicin is identical whether CCE is evoked by T-cell receptor (TCR) stimulation, heterologous muscarinic M1 receptor stimulation, or via thapsigargin depletion of internal Ca2+ stores. Patch-clamp experiments show that capsaicin rapidly and reversibly blocks I(CRAC) with an identical dose response as seen with indo-1 measurements. The major voltage-gated K+ channel in Jurkat cells, Kv1.3, is also blocked by capsaicin. Although Kv1.3 block may contribute to reducing CCE by changes in membrane potential, block of I(CRAC) is the primary mechanism by which capsaicin reduces CCE. Capsaicin analogs capsazepine and resiniferatoxin also produce inhibition of CCE via block of I(CRAC). Upon application of capsaicin to Jurkat cells in culture we observed an inhibition of interleukin-2 (IL-2) production in response to TCR stimulation. The dose dependence of capsaicin's reduction of IL-2 was comparable with its block of I(CRAC), thereby illustrating the functional relevance of capsaicin's block of lymphocyte CCE. Thus, capsaicin and its numerous analogs may have potential use as immunomodulatory drugs and should be further investigated in models of inflammation and T-cell activation.

Calcineurin inhibition ameliorates structural, contractile, and electrophysiologic consequences of postinfarction remodeling

INTRODUCTION

After myocardial infarction (MI), the heart undergoes an adaptive remodeling process characterized by hypertrophy of the noninfarcted myocardium. Calcineurin, a Ca2+-calmodulin-regulated phosphatase, has been shown to participate in hypertrophic signal transduction.

METHODS AND RESULTS

We investigated the effects of calcineurin inhibition by cyclosporin A on key structural, contractile, and electrophysiologic alterations of post-MI remodeling. Male Sprague-Dawley rats were divided into four groups: (1) sham-operated; (2) sham + cyclosporin A; (3) post-MI (left anterior descending coronary artery ligation); and (4) MI + cyclosporin A. Cyclosporin A (25 mg/kg/day) was initiated 2 days before surgery and continued for 30 days. Hypertrophy was evaluated by echocardiography and by changes in membrane capacitance of isolated myocytes from noninfarcted left ventricle (LV). The effects of cyclosporin A on hemodynamics and cardiac dimensions were investigated, and changes in diastolic function were correlated with changes in protein phosphatase 1 activity and the basal level of phosphorylated phospholamban. The effects of cyclosporin A on Kv4.2/Kv4.3 genes expression and transient outward K+ current (I(to)) density also were evaluated. One of 12 rats in the post-MI group and 2 of 12 rats in the post-MI + cyclosporin A group died within 48 hours after MI. There were no late deaths in either MI group. There was no evidence of heart failure (lung congestion and/or pleural effusion) in the two groups 4 weeks post-MI. Calcineurin phosphatase activity increased 1.9-fold in post-MI remodeled LV myocardium, and cyclosporin A administration resulted in an 86% decrease in activity. There were statistically significant decreases of LV end-diastolic pressure, LV end-diastolic diameter, and LV relative wall thickness in the post-MI + cyclosporin A group compared with the post-MI group. On the other hand, there was no significant difference in LV end-systolic diameter or peak rate of LV pressure increase between the two post-MI groups. Protein phosphatase 1 activity was elevated by 36% in the post-MI group compared with sham, and this correlated with a 79% decrease in basal level of p16-phospholamban. In the post-MI + cyclosporin A group, the increase in protein phosphatase 1 activity was much less (18% vs 36%; P < 0.05), and the decrease in basal level of p16-phospholamban was markedly ameliorated (20% vs 79%; P < 0.01). The decreases in mRNA levels of Kv4.2 and Kv4.3 and I(to) density in the LV of the post-MI + cyclosporin A group were significantly less compared with the post-MI group.

CONCLUSION

Our results show that calcineurin inhibition by cyclosporin A partially ameliorated post-MI remodeled hypertrophy, diastolic dysfunction, decrease in basal level of phosphorylated phospholamban, down-regulation of key K+ genes expression, and decrease of K+ current, with no adverse effects on systolic function or mortality in the first 4 weeks after MI.

Follicular dendritic cells: beyond the necessity of T-cell help

Follicular dendritic cells (FDCs) are potent accessory cells for B cells, but the molecular basis of their activity is not understood. Several important molecules involved in FDC-B-cell interactions are indicated by blocking the ligands and receptors on FDCs and/or B cells. The engagement of CD21 in the B-cell coreceptor complex by complement-derived CD21 ligand on FDCs delivers a crucial signal that dramatically augments the stimulation delivered by the binding of antigen to the B-cell receptor (BCR). The engagement of Fc gamma receptor IIB (FcgammaRIIB) by the Ig crystallizable fragment (Fc) in antigen-antibody complexes held on FDCs decreases the activation of immunoreceptor tyrosine-based inhibition motifs (ITIMs), mediated by the crosslinking of BCR and FcgammaRIIB. Thus, FDCs minimize a negative B-cell signal. In short, these ligand-receptor interactions help to signal to B cells and meet a requirement for B-cell stimulation that goes beyond the necessity of T-cell help.

Analysis of the cyclic nucleotide binding domain of the HERG potassium channel and interactions with KCNE2

Mutations in the cyclic nucleotide binding domain (CNBD) of the human ether-a-go-go-related gene (HERG) K+ channel are associated with LQT2, a form of hereditary Long QT syndrome (LQTS). Elevation of cAMP can modulate HERG K+ channels both by direct binding and indirect regulation through protein kinase A. To assess the physiological significance of cAMP binding to HERG, we introduced mutations to disrupt the cyclic nucleotide binding domain. Eight mutants including two naturally occurring LQT2 mutants V822M and R823W were constructed. Relative cAMP binding capacity was reduced or absent in CNBD mutants. Mutant homotetramers carry little or no K+ current despite normal protein abundance and surface expression. Co-expression of mutant and wild-type HERG resulted in currents with altered voltage dependence but without dominant current suppression. The data from co-expression of V822M and wild-type HERG best fit a model where one normal subunit within a tetramer allows nearly normal current expression. The presence of KCNE2, an accessory protein that associates with HERG, however, conferred a partially dominant current suppression by CNBD mutants. Thus KCNE2 plays a pivotal role in determining the phenotypic severity of some forms of LQT2, which suggests that the CNBD of HERG may be involved in its interaction with KCNE2.

Downregulation of K(+) channel genes expression in type I diabetic cardiomyopathy

Type I diabetic cardiomyopathy has consistently been shown to be associated with decrease of repolarising K(+) currents, but the mechanisms responsible for the decrease are not well defined. We investigated the streptozotocin (STZ) rat model of type I diabetes. We utilized RNase protection assay and Western blot analysis to investigate the message expression and protein density of key cardiac K(+) channel genes in the diabetic rat left ventricular (LV) myocytes. Our results show that message and protein density of Kv2.1, Kv4.2, and Kv4.3 are significantly decreased as early as 14 days following induction of type I diabetes in the rat. The results demonstrate, for the first time, that insulin-deficient type I diabetes is associated with early downregulation of the expression of key cardiac K(+) channel genes that could account for the depression of cardiac K(+) currents, I(to-f) and I(to-s). These represent the main electrophysiological abnormality in diabetic cardiomyopathy and is known to enhance the arrhythmogenecity of the diabetic heart. The findings also extend the extensive list of gene expression regulation by insulin.

[Elevation distribution of precipitation chemistry in middle/upper troposphere in summer, the northern slope of central Himalayas]

During 1997 summer, fresh snow samples were collected from four snowfall events from the elevation of 5800 to 7000 m in the Dasuopu Glacier region on the northern slope of Mt. Xixabangma (28 degrees 33'N, 85 degrees 44'E), in order to understand the elevation distribution of the middle/upper tropospheric components in the remote region. The correlation between SO4(2-), NO3-, Ca2+ and Mg2+ in precipitation differs with type of air mass, indicating the dominant sources of ions vary in short-term (e.g. several days) during summer low dust period. In general, with elevation increases, the concentrations of NO3-, Ca2+ and Mg2+ decreases, while SO4(2-) increases, which are influenced by the variation of dominant sources of ions.

[Therapeutic effect on glioblastoma of chemotherapy on the basis of brain irradiation]

OBJECTIVE

To study the efficacy of chemotherapy for glioblastoma on the basis of brain irradiation.

METHODS

It was previously reported that the permeability of the blood brain barrier (BBB) to methotrexate could be increased by brain irradiation. In this study, glioblastoma patients were divided into 2 groups, 28 patients in each group. On group of patients was treated with CCNU or BCNU after having given 20-40 Gy irradiation to the brain. The other group of patients received radiation treatment alone.

RESULTS

The 1-, 3-, and 5-year survival rate of the two groups of patients was 57.1%, 22.5%, 15.0% and 17.9%, 7.1%, 3.6%, respectively. The median survival time was 29.7 +/- 7.0 and 9.7 +/- 3.5 months, respectively (P < 0.001).

CONCLUSION

Increase in permeability of the BBB after 20-40 Gy brain irradiation may provide an optimal chance for intracranial chemotherapy of glioblastoma.

[Chemical characteristics of fresh snow in Mount Everest Region]

The chemistry of fresh snow samples collected in August and September, 1998 from Mount Everest was studied and compared with other fresh snow samples collected in different seasons in this region. The results indicated that major species in precipitation were very low in late summer in Mount Everest region and may be representative of the background of precipitation chemistry of remote regions in the wold. Chemical Characteristics of fresh snow in different seasons had distinct differences and they may reflect different moist source and climatic status. The precipitation in August and September was mainly come from Indian summer monsoon and in April and May it was influenced deeply by the dust of semi-arid and arid regions in central Asia. This indicates the precipitation in this region is climatic sensitively.

Alterations of sodium channel kinetics and gene expression in the postinfarction remodeled myocardium

INTRODUCTION

After a myocardial infarction (MI), the heart undergoes a remodeling process that includes hypertrophy of noninfarcted left ventricular myocytes. Alterations in the genetic expression, including reexpression of fetal isogene patterns, can result in electrophysiologic changes that contribute to the arrhythmogenicity of post-MI heart. The present study investigated possible alterations in gene expression of Na+ channel subtypes, as well as the kinetics of the Na+ current (I(Na)), in 3- to 4-week-old post-MI rat remodeled left ventricular myocardium.

METHODS AND RESULTS

Using a macropatch technique, we showed increased Na+ channel bursting activity during sustained depolarization in post-MI remodeled myocytes resulting in a large slow component of the I(Na) decay. A tetrodotoxin-sensitive current contributed 18% to the prolonged APD90 of isolated post-MI myocytes compared with 6% in control myocytes. Our molecular studies revealed that, in addition to the rat heart I (rH I) subtype, thought to be the predominant subtype that encodes a tetrodotoxin-resistant isoform, the brain subtypes NaCh I and NaCh Ia also are expressed in the rat myocytes. Post-MI remodeled myocardium showed increased expression of NaCh I protein with reversion of the NaCh Ia/NaCh I isoform ratio toward the fetal phenotype.

CONCLUSION

Our findings raise the possibility that the increase in the slow component of I(Na) in post-MI remodeled myocytes is secondary to the increased expression of NaCh I. Additional studies are required to address these questions and to characterize the functional role of the NaCh I subtypes in cardiac myocytes.

Follicular dendritic cell accessory activity crosses MHC and species barriers

Productive follicular dendritic cell (FDC)-B cell interactions appear to involve critical ligand-receptor interactions. Immune complexes (IC) on FDC activate complement and provide FDC with a complement-derived CD21 ligand (CD21L), which bind CD21, while antigen in the IC binds on the B cell-BCR. Further, FDC-FcgammaRIIB binds Fc regions of antibodies in IC and reduces coligation of BCR and FcgammaRIIB minimizing an inhibitor of B cell activation. Given that Fc receptors and complement receptors bind immunoglobulins and complement fragments of other species, we reasoned that FDC accessory activity should cross MHC and species barriers. This prediction was tested using memory lymphocytes from OVA-immune mice and TT-immune humans in combination with FDC from murine lymph nodes and human tonsils. Human and murine FDC converted IC into potent immunogens (specific antibody increased from background to thousands of ng / ml). MHC barriers did not restrict this activity and human FDC worked with murine lymphocytes and murine FDC worked with human lymphocytes. Furthermore, stimulation via MHC-dependent allogeneic or zenogeneic mechanisms did not promote antibody production by FDC. Polyclonal responses stimulated by lipopolysaccharide and pokeweed mitogen were also promoted (10 - 100-fold) and anti-CD21 blocked FDC activity. These results substantiate the hypothesis that FDC are necessary for strong recall responses and that FDC-CD21L is critical.

Structure of the FHA1 domain of yeast Rad53 and identification of binding sites for both FHA1 and its target protein Rad9

Forkhead-associated (FHA) domains have been shown to recognize both pThr and pTyr-peptides. The solution structures of the FHA2 domain of Rad53 from Saccharomyces cerevisiae, and its complex with a pTyr peptide, have been reported recently. We now report the solution structure of the other FHA domain of Rad53, FHA1 (residues 14-164), and identification of binding sites of FHA1 and its target protein Rad9. The FHA1 structure consists of 11 beta-strands, which form two large twisted anti-parallel beta-sheets folding into a beta-sandwich. Three short alpha-helices were also identified. The beta-strands are linked by several loops and turns. These structural features of free FHA1 are similar to those of free FHA2, but there are significant differences in the loops. Screening of a peptide library [XXX(pT)XXX] against FHA1 revealed an absolute requirement for Asp at the +3 position and a preference for Ala at the +2 position. These two criteria are met by a pThr motif (192)TEAD(195) in Rad9. Surface plasmon resonance analysis showed that a pThr peptide containing this motif, (188)SLEV(pT)EADATFVQ(200) from Rad9, binds to FHA1 with a K(d) value of 0.36 microM. Other peptides containing pTXXD sequences also bound to FHA1, but less tightly (K(d)=4-70 microM). These results suggest that Thr192 of Rad9 is the likely phosphorylation site recognized by the FHA1 domain of Rad53. The tight-binding peptide was then used to identify residues of FHA1 involved in the interaction with the pThr peptide. The results are compared with the interactions between the FHA2 domain and a pTyr peptide derived from Rad9 reported previously.

Early down-regulation of K+ channel genes and currents in the postinfarction heart

INTRODUCTION

Down-regulation of key K+ channel subunit gene expression and K+ currents is a universal response to cardiac hypertrophy, whatever the cause, including the postmyocardial infarction (post-MI) remodeled heart.

METHODS AND RESULTS

We investigated the hypothesis that down-regulation of K+ channel genes and currents post-MI occurs early and before significant remodeled hypertrophy of the noninfarcted myocardium could be detected. We investigated (1) the incidence of induced ventricular tachyarrhythmias (VT) in 3-day post-MI rat heart; (2) action potential (AP) characteristics of isolated left ventricular (LV) myocytes from sham-operated and 3-day post-MI heart; (3) time course of changes in outward K+ currents Ito-fast(f) and I(K) in isolated myocytes from 3-day and 4-week post-MI noninfarcted LV and compared the changes with sham-operated animals; and (4) changes in the messenger and protein levels of Kv2.1, Kv4.2, and Kv4.3 in the LV and right ventricle of 3-day post-MI heart. Sustained VT was induced in 6 of 10 3-day post-MI rats and in none of 8 sham rats. The membrane capacitance of myocytes isolated from 3-day post-MI noninfarcted LV was not significantly different from control, whereas membrane capacitance 4-week post-MI was significantly higher, reflecting the development of hypertrophy. AP duration was increased and the density of Ito-f and I(K) were significantly decreased in 3-day post-MI LV myocytes compared with sham. The reduced density of Ito did not significantly differ in 4-week post-MI LV myocytes, whereas the density of I(K) was decreased further at 4 weeks post-MI. The changes in Ito-f and I(K) correlated with decreased messenger and protein levels of Kv4.2/Kv4.3 and Kv2.1, respectively.

CONCLUSION

These results support the hypothesis that down-regulation of K+ channel gene expression and current in the post-MI LV occurs early and may be dissociated from the slower time course of post-MI remodeled hypertrophy. These changes may contribute to early arrhythmogenesis of the post-MI heart.

Effect of endothelin-1 on the biological changes of the corpus luteum regression process

The present study was conducted to evaluate whether apoptosis occurs during the corpus luteum (CL) regression process in rats, and, if so, to determine the effect of endothelin-1 (ET-1) in this process. In order to obtain CL cells, immature female rats were treated with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) to cause hyperovulation. CL cells were treated with three different dosages of ET-1 (1.0 x 10(-5) M, 1.0 x 10(-7) M, and 1.0 x 10(-9) M). The occurrence of apoptosis, intracellular calcium concentrations, and progesterone production were measured to determine the biological changes in the CL cells. We found that apoptosis occurs during CL regression accompanied by an increase in intracellular calcium, while progesterone production was decreased. ET-1 promotes the apoptosis through an increase in the intracellular calcium in the CL cells and affects the physiological function of CL cells by inhibiting progesterone production. ET-1 was shown to be an important regulator of CL during its regression.

Fc gamma receptor IIB on follicular dendritic cells regulates the B cell recall response

Generation of the B cell recall response appears to involve interaction of Ag, in the form of an immune complex (IC) trapped on follicular dendritic cells (FDCs), with germinal center (GC) B cells. Thus, the expression of receptors on FDC and B cells that interact with ICs could be critical to the induction of an optimal recall response. FDCs in GCs, but not in primary follicles, express high levels of the IgG Fc receptor Fc gamma RIIB. This regulated expression of Fc gamma RIIB on FDC and its relation to recall Ab responses were examined both in vitro and in vivo. Trapping of IC in spleen and lymph nodes of Fc gamma RII-/- mice was significantly reduced compared with that in wild-type controls. Addition of ICs to cultures of Ag-specific T and B cells elicited pronounced Ab responses only in the presence of FDCs. However, FDCs derived from Fc gamma RIIB-/- mice supported only low level Ab production in this situation. Similarly, when Fc gamma RIIB-/- mice were transplanted with wild-type Ag-specific T and B cells and challenged with specific Ag, the recall responses were significantly depressed compared with those of controls with wild-type FDC. These results substantiate the hypothesis that FcgammaRIIB expression on FDCs in GCs is important for FDCs to retain ICs and to mediate the conversion of ICs to a highly immunogenic form and for the generation of strong recall responses.

Effect of retinoic acid and its complexes with transition metals on human bladder cancer cell line EJ in vitro

The aim of this study was to investigate the effect of retinoic acid (RA) and its complexes with transition metals on the bladder cancer cell line EJ. Retinoic acid complexes with transition metals Cu, Co, Zn, and Ni were prepared. Cell proliferation was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in the presence of RA or its complexes with transition metals Cu, Co, Zn, and Ni ¿Cu(RA)2.3H2O, Co(RA)2.3H2O, Zn(RA)2.4H2O, and Ni(RA)2.3H2O¿. Colony formation in soft agar culture, A agglutination reaction, and lactic acid dehydrogenase isoenzyme assay were performed in the cells treated with these drugs to estimate the induced differentiation. p53 or c-Ha-ras expression in drug-treated cells was assayed by ABC immunocytochemistry technique. The results demonstrate that EJ cells treated with the drugs become less confluent and tend to exhibit normal characteristics. Although RA and its complexes showed inhibition to proliferation of EJ cells at the concentrations of 10(-6) mmol/l, the inhibition induced by Ni(RA)2.3H2O was much more marked than that by RA. EJ cells were growth inhibited by RA or Ni(RA)2.3H2O from 48 to 96 h at the concentration of 10(-8) mol/l. The levels of LDH4 and LDH5 in the cells were greatly increased by RA. Nevertheless, Ni(RA)2.3H2O did not affect LDH isoenzyme in EJ cells. The number of colony formations of EJ cells in soft agar culture was decreased by RA or Ni(RA)2.3H2O. The percentage of colony formation in soft agar culture was much lower in EJ cells treated with Ni(RA)2.3H2O than with RA. The required concentration of A agglutination reaction was more increased for EJ cells treated with RA or Ni(RA)2.3H2O than for the control and was further increased in cells treated with Ni(RA)2.3H2O. Mutant p53 expression was more decreased in the EJ cells treated with RA or Ni(RA)2.3H2O than in the control. Although RA at the concentration of 10(-6) mmol/l caused lower p21 expression, Ni(RA)2.3H2O did not affect p21 expression in EJ cells. Therefore, RA and its transition metal complexes have a potential use in the treatment of bladder cancer.

Reexpression of T-type Ca2+ channel gene and current in post-infarction remodeled rat left ventricle

OBJECTIVE

T-type Ca2+ currents (I(Ca-T)) are present in neonatal rat myocytes but is not detected in adult ventricular myocytes. The present study was designed to investigate the expression of the T-type Ca2+ channel gene and current in post-infarction remodeled hypertrophied rat left ventricle (LV).

METHODS

We compared the expression of T-type Ca2+ channel gene alpha-1G in neonatal rat LV, in adult sham-operated LV and remodeled hypertrophied LV 3 to 4 weeks post-myocardial infarction (MI) using RNase protection assay (RPA). The cDNA fragment of alpha-1G used in RPA was obtained from poorly conserved region of recently published T-type Ca2+ channel coding sequence of rat by RT-PCR. The fragment was verified by restriction enzyme digestion and sequencing. The presence of I(Ca-T) in LV of sham and post-MI rats was examined using patch-clamp techniques. In the presence of K+-free, Na+-free external solution, I(Ca-T) was separated from I(Ca-L) by different holding potentials (HP). I(Ca-T) was also recorded during depolarization to -40 mV from a HP of -80 mV with NaCl in external solution and I(Na) suppressed by 100 microM tetrodotoxin (TTX).

RESULTS

The T-type Ca2+ channel gene alpha-1G was expressed in neonatal heart, the expression level decreased by 80%, in adult sham heart and was reexpressed in MI (158% increases compared to sham; P<0.01). I(Ca-T) was recorded in 11 of 31 MI cells in presence of K+-free, Na+-free external solution and in 9 of 14 cells when I(Na) was suppressed by TTX. I(Ca-T) was not detected in any of 21 sham cells. I(Ca-T) density was 1.1+/-0.4 pA/pF. I(Ca-T) was more sensitive to Ni2+ and less sensitive to nisoldipine.

CONCLUSIONS

T-type Ca2+ channel gene and current are reexpressed in rat post-MI remodeled LV myocytes. Its functional significance in the post-MI remodeling process remains to be defined.

Inhibition of protein kinase C(alpha) by dequalinium analogues: dependence on linker length and geometry

Analogues of a bipartite compound, dequalinium (DECA) (quinolinium, 1,1'-(1,10-decanediyl)bis(4-amino-2-methyl diiodide)), were tested for inhibition of protein kinase C(alpha) (PKC(alpha)). In vitro assays of monomeric and dimeric analogues support a model in which DECA inhibits PKC(alpha) by an obligatory two-point contact, a unique mechanism among PKC inhibitors. The presence of unsaturation in the center of the C(10)-alkyl linker produced geometric isomers with different inhibitory potencies: cis IC(50) = 52 +/- 12 microM and trans IC(50) = 12 +/- 3 microM, where the trans isomer was equipotent to that of the saturated C(10)-DECA. DECA analogues with longer, saturated linkers (C(12), C(14), or C(16)) exhibited enhanced inhibitory potencies which reached a plateau with the C(14)-linker (IC(50) = 2.6 +/- 0.2 microM). Metastatic melanoma cells treated with 250 nM C(12)-, C(14)-, or C(16)-DECA and irradiated with long-wave UV light (which causes irreversible inhibition of PKC(alpha) by DECA) confirmed the linker-dependent inhibition of intracellular PKC(alpha) activity.

Tumor suppressor INK4: quantitative structure-function analyses of p18INK4C as an inhibitor of cyclin-dependent kinase 4

We report the first detailed structure-function analyses of p18INK4C (p18), which is a homologue of the important tumor suppressor p16INK4A (p16). Twenty-four mutants were designed rationally. The global conformations of the mutants were characterized by NMR, while the function was assayed by inhibition of cyclin-dependent kinase 4 (CDK4). Most of these mutants have unperturbed global structures, thus the changes in their inhibitory abilities can be attributed to the mutated residues. The important results are summarized as follows: (a) some residues at loops 1 and 2, but not 3, are important for the inhibitory function of p18, similar to the results for p16; (b) two residues at the first helix-turn-helix motif and two at the third are important for inhibition; (c) while the results generally agree with the prediction based on the crystal structures of p16-CDK6 and p19-CDK6 binary complexes, there are significant differences in a few residues, suggesting that the interactions in the binary complexes may not accurately represent the interactions in the ternary complexes (in the presence of cyclin D2); (d) most importantly, the extra loop of p18 appears to contribute to the function of p18, even though the crystal structure of the p19INK4D-CDK6 complex indicates no interactions involving this loop; (e) detailed analyses of the crystal structures and the functional results suggest that there are notable differences in the interactions between different members of the INK4 family and CDKs.

Collisional Deactivation of Highly Vibrationally Excited SO2: A Time-Resolved FTIR Emission Spectroscopy Study

Time-resolved Fourier transform IR emission spectroscopy, capable of 10

Follicular dendritic cells protect malignant B cells from apoptosis induced by anti-Fas and antineoplastic agents

The observation that follicular dendritic cells (FDC) reduce apoptosis in B cells prompted the hypothesis that FDC might enhance tumor cell survival by protecting malignant B cells from apoptotic death. To test this notion, apoptosis was induced in B cell lymphomas by anti-Fas or various antineoplastic agents in the presence and absence of FDC. Apoptosis was detected and quantified by TUNEL analysis. Induction of apoptosis with anti-Fas, etoposide, cyclophosphamide, and busulfan was markedly antagonized by FDC at FDC to B cell ratios of >/=1:16. For example, treatment with 10 ng/ml anti-Fas caused 60-90% of A20 cells to undergo apoptosis in 6 h, whereas addition of FDC reduced apoptosis to background levels (3-15%). Similarly, treatment with busulfan induced apoptosis in 55-80% of A20 cells, whereas addition of FDC reduced B cell death to </=15%; moreover, depletion of FDC abrogated the protective actions. In contrast, the apoptosis-inducing effect of Adriamycin was not reversed by FDC. The ability to block apoptosis induced by anti-Fas or busulfan was not limited to A20 but was observed in four other malignant pre-B cell or B cell lines. The mechanism by which FDC spare malignant B cells from apoptosis did not involve alterations in levels of Bcl-2, Bcl-XL, or Bax. Collectively, these data raise the possibility that FDC may enhance tumor cell survival by protecting malignant B cells against apoptosis induced by anti-Fas and some but not all chemotherapeutic agents.

Diminished basal phosphorylation level of phospholamban in the postinfarction remodeled rat ventricle: role of beta-adrenergic pathway, G(i) protein, phosphodiesterase, and phosphatases

Three weeks after myocardial infarction (MI) in the rat, remodeled hypertrophy of noninfarcted myocardium is at its maximum and the heart is in a compensated stage with no evidence of heart failure. Our hemodynamic measurements at this stage showed a slight but insignificant decrease of +dP/dt but a significantly higher left ventricular end-diastolic pressure. To investigate the basis of the diastolic dysfunction, we explored possible defects in the beta-adrenergic receptor-G(s/i) protein-adenylyl cyclase-cAMP-protein kinase A-phosphatase pathway, as well as molecular or functional alterations of sarcoplasmic reticulum Ca(2+)-ATPase and phospholamban (PLB). We found no significant difference in both mRNA and protein levels of sarcoplasmic reticulum Ca(2+)-ATPase and PLB in post-MI left ventricle compared with control. However, the basal levels of both the protein kinase A-phosphorylated site (Ser16) of PLB (p16-PLB) and the calcium/calmodulin-dependent protein kinase-phosphorylated site (Thr17) of PLB (p17-PLB) were decreased by 76% and 51% in post-MI myocytes (P<0.05), respectively. No change was found in the beta-adrenoceptor density, G(salpha) protein level, or adenylyl cyclase activity. Inhibition of phosphodiesterase and G(i) protein by Ro-20-1724 and pertussis toxin, respectively, did not correct the decreased p16-PLB or p17-PLB levels. Stimulation of beta-adrenoceptor or adenylyl cyclase increased both p16-PLB and p17-PLB in post-MI myocytes to the same levels as in sham myocytes, suggesting that decreased p16-PLB and p17-PLB in post-MI myocytes is not due to a decrease in the generation of p16-PLB or p17-PLB. We found that type 1 phosphatase activity was increased by 32% (P<0.05) with no change in phosphatase 2A activity. Okadaic acid, a protein phosphatase inhibitor, significantly increased p16-PLB and p17-PLB levels in post-MI myocytes and partially corrected the prolonged relaxation of the [Ca(2+)](i) transient. In summary, prolonged relaxation of post-MI remodeled myocardium could be explained, in part, by altered basal levels of p16-PLB and p17-PLB caused by increased protein phosphatase 1 activity.

Microfabricated polymer devices for automated sample delivery of peptides for analysis by electrospray ionization tandem mass spectrometry

Delivery of proteins and peptides to electrospray ionization mass spectrometers (ESI-MS) has been demonstrated using glass and quartz microfabricated devices. This paper reports the construction and use of poly(dimethylsiloxane) (PDMS) microfabricated soft polymer devices with mass spectrometry for protein analysis. The PDMS devices were fabricated using replica molding against a patterned photoresist generated by photolithographic techniques. The PDMS devices were connected to the mass spectrometer via a derivatized transfer capillary and samples were transferred by electroosmotic pumping. The formulation of PDMS was optimized for compatibility with ESI, and the devices were tested for performance. The practical application of PDMS devices was demonstrated by the identification of rat serum albumin separated by 2-D gel electrophoresis. Extended contact of the sample with the surface of the PDMS device did not significantly affect the sample analysis, and the limit of detection for samples run on a PDMS device was comparable to the limit of detection achieved on glass devices. This study suggests that PDMS devices fabricated using replica molding are compatible with ESI-MS. This will potentially lead to the construction of inexpensive microfabricated devices with complex designs and advanced functionalities.

[Influence of radiation on the blood-brain barrier and optimum time of chemotherapy]

OBJECTIVE

A pilot study of the destructive effects of radiation on the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB) were carried out on 29 patients.

METHODS

(1) First BBB with localized and limited brain tumors was examined by 99mTc-GH imaging count/pixel, data was obtained from the unirradiated, irradiated, and tumor areas of before and after radiotherapy of 20-40 Gy respectively. (2) The BCSFB was studied quantitatively by observing the effect of methotrexate (MTX) permeation into the CSF before, during, and after brain irradiated after i.v. injection of MTX.

RESULTS

(1) the BBB in the unirradiated area outside the radiation portal was not changed, (2) the degree of destructive effect on the BBB in the irradiated normal area and on the BCSFB were directly proportional to radiation doses.

CONCLUSIONS

When the permeation of BBB and BCSFB irradiated, was enhanced the degree of destructive effect were enhanced proportionally with irradiation doses. It was that the BBB irradiated can be recovered at least partially after irradiation of 3 weeks proved. After a dose of 20 Gy irradiation, the BCSFB would gradually open. As compared with the pre-radiation data, the permeability of MTX increased by 1.05-1.3 times. So, it was advisable to give chemotherapy after 20 Gy irradiation.

Follicular dendritic cells mediated maintenance of primary lymphocyte cultures for long-term analysis of a functional in vitro immune system

Primary lymphocyte cultures are important for analysis of cellular and molecular events occurring during immune responses. However, the lymphoid cells (especially B cells) typically only survive for a few days in vitro which limits studies. Establishment of long-term primary lymphocyte cultures where a functioning humoral immune responses can be maintained and regulated is still a challenge. Follicular dendritic cells (FDC) are immune accessory cells that reside in the follicles of secondary lymphoid organs and are known to protect lymphocytes from apoptosis. We hypothesized that addition of FDC to primary lymphocyte cultures may help maintain humoral immune responses in vitro as they do in vivo. To test the hypothesis, freshly isolated lymphocytes were cultured with or without FDC. The B cells in cultures were labeled using B220 and apoptotic cells were labeled using the TUNEL assay. Antibody production was monitored in supernatant fluids using ELISA. The results showed that FDC reduced apoptosis and helped sustain primary lymphocyte cultures and antibody production was maintained throughout the entire period (e.g., 8 weeks). This FDC dependent system should be useful for analysis of cellular and molecular events over extended periods in vitro.

Beam redirection and frequency filtering with transparent elastomeric diffractive elements

A new, to our knowledge, type of optical device capable of beam redirection and frequency filtering is described. It is based on a transparent elastomeric binary diffraction grating. When light is passed through the device the intensities of the diffraction orders can be modulated by compression of the elastomer in the direction perpendicular to the plane of the grating. Selective filtering of the component frequencies of two-component light (lambda = 543.5 nm and lambda = 632.8 nm) has been demonstrated. Experimental observations are in agreement with theoretical calculations quantifying the performance of the device.

Inhibition of viral adhesion and infection by sialic-acid-conjugated dendritic polymers

Multiple sialic acid (SA) residues conjugated to a linear polyacrylamide backbone are more effective than monomeric SA at inhibiting influenza-induced agglutination of red blood cells. However, "polymeric inhibitors" based on polyacrylamide backbones are cytotoxic. Dendritic polymers offer a nontoxic alternative to polyacrylamide and may provide a variety of potential synthetic inhibitors of influenza virus adhesion due to the wide range of available polymer structures. We evaluated several dendritic polymeric inhibitors, including spheroidal, linear, linear-dendron copolymers, comb-branched, and dendrigraft polymers, for the ability to inhibit virus hemagglutination (HA) and to block infection of mammalian cells in vitro. Four viruses were tested: influenza A H2N2 (selectively propagated two ways), X-31 influenza A H3N2, and sendai. The most potent of the linear and spheroidal inhibitors were 32-256-fold more effective than monomeric SA at inhibiting HA by the H2N2 influenza virus. Linear-dendron copolymers were 1025-8200-fold more effective against H2N2 influenza, X-31 influenza, and sendai viruses. The most effective were the comb-branched and dendrigraft inhibitors, which showed up to 50000-fold increased activity against these viruses. We were able to demonstrate significant (p < 0.001) dose-dependent reduction of influenza infection in mammalian cells by polymeric inhibitors, the first such demonstration for multivalent SA inhibitors. Effective dendrimer polymers were not cytotoxic to mammalian cells at therapeutic levels. Of additional interest, variation in the inhibitory effect was observed with different viruses, suggesting possible differences due to specific growth conditions of virus. SA-conjugated dendritic polymers may provide a new therapeutic modality for viruses that employ SA as their target receptor.