Adsorption stripping voltammetry of phenol at Nafion-modified glassy carbon electrode in the presence of surfactants

In this paper, a new voltammetric method for the determination of phenol is described. In pH 8.00 phosphate buffer and in the presence of long-chain cationic surfactant-cetyltrimethylammonium bromide-phenol has a very sensitive oxidation peak at 0.47 V (vs. SCE) on the Nafion-modified glassy carbon electrode (GCE). The experimental parameters, such as supporting electrolyte and pH values, amounts of Nafion, varieties and concentration of surfactants, accumulation potential and time, as well as scan rate were optimized. The peak current is linear with the concentration of phenol in the range from 8x10(-9) to 1x10(-5) M, and the detection limit is 1x10(-9) M after being accumulated at -0.50 V (vs. SCE) for 3 min. Trace levels of phenol in water samples were determined by using this voltammetric method, the average recovery was calculated to be 99.56%.

Social vulnerability and HIV testing among South African men who have sex with men

This study examined whether social vulnerability is associated with HIV testing among South African men who have sex with men (MSM). A community-based survey was conducted with 300 MSM in Pretoria in 2008. The sample was stratified by age, race and residential status. Social vulnerability was assessed using measures of demographic characteristics, psychosocial determinants and indicators of sexual minority stress. Being black, living in a township and lacking HIV knowledge reduced MSM's likelihood of ever having tested for HIV. Among those who had tested, lower income and not self-identifying as gay reduced men's likelihood of having tested more than once. Lower income and internalized homophobia reduced men's likelihood of having tested recently. Overall, MSM in socially vulnerable positions were less likely to get tested for HIV. Efforts to mitigate the effects of social vulnerability on HIV testing practices are needed in order to encourage regular HIV testing among South African MSM.

Effect of ionizing radiation on acinar morphogenesis of human prostatic epithelial cells under three-dimensional culture conditions

Homeostasis is maintained by the interplay of multiple factors that directly or indirectly regulate cell proliferation and cell death. Complex multiple interactions between cells and the extracellular matrix occur during acinar morphogenesis and changes in these might indicate carcinogenesis of cells from a normal to a malignant, invasive phenotype. In this study, the human prostatic epithelial cell line RWPE-1 was cultured under three-dimensional (3-D) culture conditions, and the effect of ionizing radiation on acinar morphogenesis and its association with autophagy were discussed. The results illustrated that formation of specific spheroid (acinar) structures was detectable under 3-D culture conditions. Radiation induced the disruption of acini in different cell models using either gene overexpression (Akt) or gene knock-down (Beclin 1 and ATG7). Introduction of Akt not only accelerated the growth of cells (i.e., caused the cells to manifest elongating and microspike-like structures that are obviously different from structures seen in wild-type RWPE-1 cells under two-dimensional conditions), but also changed their morphological characteristics under 3-D culture conditions. Knock-down of autophagy-related genes (Beclin 1 and ATG7) increased the radiosensitivity of cells under 3-D culture conditions, and cells died of non-apoptotic death after radiation. The results suggested that ionizing radiation may change the cell phenotype and the formation of acini. Additionally even the autophagy mechanism may play a role in these processes.

S-1 monotherapy for the treatment of elderly patients with advanced gastric cancer

e15671

Background: Elderly patients have often been excluded from clinical trials and only limited data are available regarding treatment of these patients. The efficacy of S-1 chemotherapy for elderly patients with advanced gastric cancer (AGC) is not well investigated. The aim of this study is to evaluate the efficacy and safety of S-1 monotherapy in elderly patients with AGC to whom conventional chemotherapy is difficult to deliver. Methods: From January 1, 2007 to August 31, 2008, a total of seventeen patients older than 70 were given S1 monotherapy. They received S-1 at a dose of 40mg/m2 BID either every 3 weeks (2 weeks on, 1 week off) or every 6 weeks (4 weeks on, 2 weeks off). Response was assessed according to RECIST criteria. Results: The patients consisted of 11 men and 6 women whose median age was 77 years (range: 71–83) with their performance status in 1 to 2. Five patients had recurrent AGC and the other 12 patients metastatic AGC at the time of diagnosis. Total 89 cycles of S-1 chemotherapy were given (median 4 cycles, range 2–12). Fifteen patients were evaluable for response because of early death in 2 patients. Response rate was 17.6% (95% Condifence Interval, 0 to 35.7); Complete remission in 0, partial remission in 3 (17.6%) and stable disease in 5 patients (29.4%). At a median follow up of 9.7 months (range: 8–11.4), median progression free survival was 5.1 months (range: 3.5–6.7) and overall survival was 9.5 months (range: 5.6–15.5). Most of the adverse effects of S1 monotherapy did not extend beyond grade 3. Grade 3 or 4 non- hematologic toxicities were not frequent and were easily manageable except in two, one of whom died of neutropenic sepsis and the other who died of subdural hemorrhage in grade 4 thrombocytopenia. Conclusions: S1 chemotherapy showed modest efficacy in elderly patients with AGC. The hematologic toxicity should be cautiously monitored in these elderly patients to avoid fatal events. Further studies are warranted for optimal management of elderly patients with metastatic or recurrent AGC.

No significant financial relationships to disclose.

HIV testing and self-reported HIV status in South African men who have sex with men: results from a community-based survey

OBJECTIVE

To investigate the characteristics of South African men who have sex with men (MSM) who (1) have been tested for HIV and (2) are HIV positive.

METHODS

Data were collected from 1045 MSM in community surveys using questionnaires that were administered either face-to-face, by mail or on the internet. The mean age of the men was 29.9 years. The race distribution was 35.3% black, 17.0% coloured, 5.3% Indian and 41.1% white.

RESULTS

The proportion of MSM tested for HIV was 69.7%; having been tested was independently associated with being older, being more open about one's homosexuality and being homosexually instead of bisexually attracted; black MSM, students and MSM living in KwaZulu-Natal were less likely to have been tested. Of the 728 MSM who had been tested, 14.1% (n = 103) reported to be HIV positive (9.9% of the total sample). Being HIV positive is independently associated with two factors: men who were positive were more likely to have a lower level of education and to know other people who had HIV/AIDS; race was not independently associated with HIV status among those who had been tested.

CONCLUSIONS

The likelihood of having been tested for HIV seems to decrease with increasing social vulnerability. Racially, the distribution of HIV among MSM seems to differ from that of the general South African population, suggesting that while intertwined with the heterosexual epidemic there is also an epidemic among South African MSM with specific dynamics. These findings suggest that in-depth research is urgently needed to address the lack of understanding of HIV testing practices and HIV prevalence in South African MSM.

Haploinsufficiency of RanBP2 is neuroprotective against light-elicited and age-dependent degeneration of photoreceptor neurons

Prolonged light exposure is a determinant factor in inducing neurodegeneration of photoreceptors by apoptosis. Yet, the molecular bases of the pathways and components triggering this cell death event are elusive. Here, we reveal a prominent age-dependent increase in the susceptibility of photoreceptor neurons to undergo apoptosis under light in a mouse model. This is accompanied by light-induced subcellular changes of photoreceptors, such as dilation of the disks at the tip of the outer segments, prominent vesiculation of nascent disks, and autophagy of mitochondria into large multilamellar bodies. Notably, haploinsufficiency of Ran-binding protein-2 (RanBP2) suppresses apoptosis and most facets of membrane dysgenesis observed with age upon light-elicited stress. RanBP2 haploinsufficiency promotes decreased levels of free fatty acids in the retina independent of light exposure and turns the mice refractory to weight gain on a high-fat diet, whereas light promotes an increase in hydrogen peroxide regardless of the genotype. These studies demonstrate the presence of age-dependent and RanBP2-mediated pathways modulating membrane biogenesis of the outer segments and light-elicited neurodegeneration of photoreceptors. Furthermore, the findings support a mechanism whereby the RanBP2-dependent production of free fatty acids, metabolites thereof or the modulation of a cofactor dependent on any of these, promote apoptosis of photoreceptors in concert with the light-stimulated production of reactive oxygen species.

Prediction of response to chemotherapy using sequential F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) in patients with metastatic colorectal cancer

2536

Background: Clinical response is determined after 2 or 3 cycles of chemotherapy by changes in tumor size as assessed by conventional imaging procedures such as computed tomography (CT). The aim of this study was to evaluate the use of sequential F-18 FDG PET to predict response to standardized chemotherapy for metastatic colorectal cancer (mCRC). Methods: Clinical response, as assessed by RECIST criteria, served as the reference. Investigators were free to choose chemotherapy regimen. F-18 FDG PET images after every second cycles of chemotherapy were analyzed semiquantitatively for each metastatic lesion using standardized uptake values (SUVs) normalized to patients’ blood glucose levels. PET responses were prospectively assessed as either complete metabolic response (CMR), partial metabolic response (PMR), stable metabolic disease (SMD), or progressive metabolic disease (PMD). In addition, sum of SUV of all metastatic lesions (sSUV) and a maximal SUV (mSUV) were recorded each PET-CT scan. Results: Twenty-four patients underwent 73 PET-CT scans since March 2005. The response to chemotherapy included CR in 1 (4.2%), PR in 10 (42%) by RECIST criteria. Median duration of follow- up was 8.3 months (range, 1.7 - 16.2) and median progression free survival (PFS) time was 6.4 months. At the baseline evaluation, PET-CT was the more sensitive test to find metastatic lesion than conventional assessment in 12 (50.0%). Baseline sSUV and mSUV was not significantly different between clinical responders and non-responders. After 2 cycles of chemotherapy, sSUV and mSUV was more decreased in clinical responder with significance (P=.023 and .020, respectively). In the 22 evaluable patients, PET responses were as followed: CMR in 1 (4.5%), PMR in 11 (50.0%), SMD in 7 (31.8%) and PMD in 3 (12.0%). Estimated median PFS was significantly prolonged in metabolic responders: PMR 8.3 months, SMD 4.7 months and PMD 2.3 months (P=.040). Patient with CMR had no evidence of progression for 14.7 month follow-up. Conclusions: In patients with mCRC, sequential FDG-PET predicted PFS and was more accurate than clinical response criteria. FDG- PET appears to be a promising tool for early prediction of response to chemotherapy.

No significant financial relationships to disclose.

Neuroprotection by propargylamines in Parkinson's disease: intracellular mechanism underlying the anti-apoptotic function and search for clinical markers

In Parkinson's and other neurodegenerative diseases, a therapeutic strategy has been proposed to halt progressive cell death. Propargylamine derivatives, rasagiline and (-)deprenyl (selegiline), have been confirmed to protect neurons against cell death induced by various insults in cellular and animal models of neurodegenerative disorders. In this paper, the mechanism and the markers of the neuroprotection are reviewed. Propargylamines prevent the mitochondrial permeabilization, membrane potential decline, cytochrome c release, caspase activation and nuclear translocation of glyceraldehyde 3-phosphate dehydrogenase. At the same time, rasagiline induces anti-apoptotic pro-survival proteins, Bcl-2 and glial cell-line derived neurotrophic factor, which is mediated by activated ERK-NF-kappaB signal pathway. DNA array studies indicate that rasagiline increases the expression of the genes coding mitochondrial energy synthesis, inhibitors of apoptosis, transcription factors, kinases and ubiquitin-proteasome system, sequentially in a time-dependent way. Products of cell survival-related gene induced by propargylamines may be applied as markers of neuroprotection in clinical samples.

Involvement of type A monoamine oxidase in neurodegeneration: regulation of mitochondrial signaling leading to cell death or neuroprotection

In neurodegenerative diseases, including Parkinson's and Alzheimer's diseases, apoptosis is a common type of cell death, and mitochondria emerge as the major organelle to initiate death cascade. Monoamine oxidase (MAO) in the mitochondrial outer membrane produces hydrogen peroxide by oxidation of monoamine substrates, and induces oxidative stress resulting in neuronal degeneration. On the other hand, a series of inhibitors of type B MAO (MAO-B) protect neurons from cell death. These results suggest that MAO may be involved in the cell death process initiated in mitochondria. However, the direct involvement of MAO in the apoptotic signaling has been scarcely reported. In this paper, we present our recent results on the role of MAO in activating and regulating cell death processing in mitochondria. Type A MAO (MAO-A) was found to bind an endogenous dopaminergic neurotoxin, N-methyl(R)salsolinol, and induce apoptosis in dopaminergic SH-SY5Y cells containing only MAO-A. To examine the intervention of MAO-B in apoptotic process, human MAO-B cDNA was transfected to SH-SY5Y cells, but the sensitivity to N-methyl(R)salsolinol was not affected, even though the activity and protein of MAO-B were expressed markedly. MAO-B oxidized dopamine with production of hydrogen peroxide, whereas in control cells expressing only MAO-A, dopamine autoxidation produced superoxide and dopamine-quinone, and induced mitochondrial permeability transition and apoptosis. Rasagiline and other MAO-B inhibitors prevent the activation of apoptotic cascade and induce prosurvival genes, such as bcl-2 and glial cell line-derived neurotrophic factor, in MAO-A-containing cells. These results demonstrate a novel function of MAO-A in the induction and regulation of apoptosis. Future studies will clarify more detailed mechanism behind regulation of mitochondrial death signaling by MAO-A, and bring out new strategies to cure or ameliorate the decline of neurons in neurodegenerative disorders.

Presence of functional mouse regulatory CD4+CD25+T cells in xenogeneic neonatal porcine thymus-grafted athymic mice

Xenotransplantation with porcine thymus is emerging as a possible means to reconstitute host cellular immunity and to induce immune tolerance in rodents and large animals. However, the presence of regulatory T cells (Treg cells) in this model needs to be determined. We herein demonstrated that efficient repopulation of mouse CD4+CD25+Treg cells was achieved in Balb/c nude mice by grafting neonatal porcine thymic tissue (NP THY). Mouse CD4+CD25+T cells expressed normal levels of Foxp3 in NP THY-grafted nude mice. Furthermore, these CD4+CD25+Treg cells showed significant inhibitory effects on the cell proliferation or interleukin-2 products of syngeneic T cells to alloantigens, Con A or a peptide antigen, although the potent immunosuppressive function might be lower than CD4+CD25+Treg cells in Balb/c mice. CD4+CD25+T cells in NP THY-grafted nude mice showed significantly stronger inhibition on the response to donor porcine antigens of CD4+CD25(-)T cells than CD4+CD25+Treg cells in Balb/c mice. Both CD4+CD25+Treg cells in NP THY-grafted nude and Balb/c mice prevented the development of autoimmune disease mediated by syngeneic CD4+CD25(-)T cells in a similar efficient way in the secondary recipients. These findings provide evidence for the potential involvement of CD4+CD25+Treg cells in keeping self-tolerance and transplant tolerance in this xeno-thymus transplantation model.

Three-day regimen of fluorouracil and cisplatin combination chemotherapy for persistence, metastatic or recurrent uterine cervical cancer

15049

Background: The five-day infusion of FP(5-fluorouracil, cisplatin) combination therapy is one of the most popular regimens for advanced cervical cancer, which has yield a 50∼60% response rate. There is some variance in the FP combination, for example, longer infusion of FP requiring longer hospitalization as well as causing more discomfort to the patients. This study was designed to assess the therapeutic effect and toxicities of three day regimen of FP combination chemotherapy instead of five day regimen for disseminated or recurrent cervical cancer. Methods: From July 1996 through April 2001, 39 patients with advanced or recurrent cervical cancer were enrolled in the study. The regimen consisted of continuous 12-hour infusion of 5-FU(5-fluorouracil) at 1000 mg/m2/day plus bolus infusion of cisplatin at 25mg/m2/day for 3 days. The treatment was repeated every 3 weeks. Results: Thirty five patients with a median age of 53 years were evaluable for response during the median follow up of 21.5 months. The response rate was 45.7% (4 CR and 12 PR), and the median duration of the overall survival was 45 months. Toxicity was acceptable with no treatment related mortality. Neutropenia in grade 3 or more was seen in 16% with 4 febrile episodes throughout a total 232 cycles. It did not appear alopecia and gastointestinal trouble in grade 3 or more. Conclusions: These results revealed that the toxicity of 3 day regimen of 5-FU and cisplatin is acceptable and the efficacy comparable to that of 5 day regimen.

No significant financial relationships to disclose.

Neuromelanin induces oxidative stress in mitochondria through release of iron: mechanism behind the inhibition of 26S proteasome

Parkinson's disease is characterized by the selective depletion of dopamine neurons in the substantia nigra, particular those containing neuromelanin. Involvement of neuromelanin in the pathogenesis may be either cytotoxic or protective. Recently we found that neuromelanin reduces the activity of 26S proteasome. In this paper, the detailed mechanisms behind the reduced activity were studied using neuromelanin isolated from the human brain. Neuromelanin increased the oxidative stress, but synthetic melanin did not. Superoxide dismutase and deferoxamine completely suppressed the increase, indicating that superoxide produced by an iron-mediated reaction plays a central role. Iron was shown to reduce in situ 26S proteasome activity in SH-SY5Y cells and the reduction was protected by antioxidants. These results suggest that iron released from neuromelanin increases oxidative stress in mitochondria, and then causes mitochondrial dysfunction and reduces proteasome function. The role of neuromelanin is discussed in relation to the selective vulnerability of dopamine neurons in Parkinson's disease.

An emerging HIV risk environment: a preliminary epidemiological profile of an MSM POZ Party in New York City

OBJECTIVE

To develop a preliminary epidemiological description of a men who have sex with men (MSM) "POZ Party," an emerging sex environment for HIV+ MSM.

METHODS

As part of a pilot study in New York City in 2003, data were collected using a brief, behavioural intercept survey at entry to POZ Party events. Domains include demographic characteristics, history of HIV infection, motivations for attending POZ parties, lifetime and recent exposure to drugs (including use during POZ Party events), and recent sexual practices (both within both POZ Party venues as well as in non-POZ Party venues).

RESULTS

Predominantly white and over the age of 30, subjects in the sample include a broad range of years living with HIV infection. Motivations for using a POZ Party venue for sexual partnering include relief from burdens for serostatus disclosure, an interest in not infecting others, and opportunities for unprotected sexual exchange. High rates of unprotected sex with multiple partners are prevalent in the venue. Although the sample evidences high rates of lifetime exposure to illicit drugs, relatively little drug use was reported in these sexual environments. These reports are consistent with evidence from direct observation at the venues themselves, in which no drug use was apparent.

CONCLUSION

Serosorting among HIV+ MSM may reduce new HIV infections, a stated interest of both POZ Party organisers and participants alike. However, high rates of unprotected anal intercourse within these venues signal continued risk for STIs. Additionally, unprotected sexual contact with HIV partners and status unknown partners outside POZ Party venues heightens concern for diffusion of HIV superinfection.

Overexpression of amyloid precursor protein induces susceptibility to oxidative stress in human neuroblastoma SH-SY5Y cells

In Alzheimer's disease amyloid beta peptide (Abeta) produced from amyloid precursor protein (APP) is considered to induce cell death. To clarify the molecular mechanism underlying Abeta neurotoxicity, we established the cell line overexpressing wild or mutant (His684Arg) APP in human SH-SY5Y cells. This paper presents that overexpression of wild-APP in the cells (SH/w-APP) increased the levels of APP and Abeta(1-40) but not Abeta(1-42), and reduced Bcl-2 level and proteasome activity with increased susceptibility to oxidative stress. The intracellular levels of reactive oxygen species in SH/w-APP increased significantly by H(2)O(2) treatment. The level of Bcl-2 protein, but not mRNA, was markedly decreased in SH/w-APP cells, which was inversely correlated with APP expression among subcloned SH/w-APP cells. These results indicate that increased expression of wild type APP renders neuronal cells more vulnerable to oxidative stress leading to cell death.

N-Propargylamine protects SH-SY5Y cells from apoptosis induced by an endogenous neurotoxin, N-methyl(R)salsolinol, through stabilization of mitochondrial membrane and induction of anti-apoptotic Bcl-2

Propargylamine derivatives, rasagiline and (-)deprenyl, are anti-Parkinson agents and protect neurons from cell death as shown by in vivo and in vitro experiments. The studies on the chemical structure-activity relationship proved that the propargyl moiety is essentially required for the neuroprotective function. In this paper, neuroprotective activity of free N-propargylamine was studied using SH-SY5Y cells expressing only type A monoamine oxidase (MAO) against apoptosis induced by an endogenous dopaminergic neurotoxin, N-methyl(R)salsolinol. N-Propargylamine prevented apoptosis, whereas N-methylpropargylamine and propiolaldehyde did not. N-Propargylamine stabilized mitochondrial membrane potential and induced anti-apoptotic Bcl-2 at 1 microM-10 nM. N-Propargylamine inhibited MAO-A in competition to substrate with the apparent K(i) value of 28 microM, which was significantly higher than the concentration required for neuroprotection. It indicates that MAO inhibition is not prerequisite for the protective function of N-propargylamine. The anti-apoptotic function of N-propargylamine is discussed in terms of neuroprotection by propargylamines in neurodegenerative diseases, including Parkinson's disease.

Search for pi(0)-->nu(mu)nu(mu) decays in the LSND detector

We observe a net beam excess of 8.7+/-6.3(stat)+/-2.4(syst) events, above 160 MeV, resulting from the charged-current reaction of nu(micro) and/or nu;(mu) on C and H in the LSND detector. No beam-related muon background is expected in this energy regime. Within an analysis framework of pi(0)-->nu(mu)nu;(mu), we set a direct upper limit for this branching ratio of Gamma(pi(0)-->nu(mu)nu;(mu))/Gamma(pi(0)-->all)<1.6 x 10(-6) at 90% confidence level.

Spontaneous N incorporation onto a Si(100) surface

Initial nitridation of the Si(100) surface is investigated using photoemission, ion-scattering and ab initio calculations. After dissociation of NO or NH3, nitrogen atoms are found to spontaneously form a stable, highly coordinated N[triple bond]Si(3) species even at room temperature. The majority of the N species is incorporated into the subsurface Si layers occupying an interstitial site, whose atomic structure and unique bonding mechanism is clarified through ab initio calculations. This unusual adsorption behavior elucidates the atomistic mechanism of initial silicon nitride formation on the surface and has important implication on the N-rich layer formation at the SiO(x)N(y)/Si interface.

Usefulness of silicone plate for sellar floor reconstruction

During the transsphenoidal approach (TSA), the proper sellar floor reconstruction plays an important role in the surgical results. The authors have evaluated the usefulness of a silicone as a substitute for bone splint in sellar floor reconstruction. Silicone plates were used in 10 patients who had 7 pituitary adenomas, 2 Rathke's cleft cysts, and 1 metastatic tumor. Among the ten cases, seven underwent standard TSAs and three received extended TSAs. The silicone plate was cut to a size slightly larger than that of bone window, inserted with a three-pronged fork, and then adjusted precisely. In nine patients, complications that related to surgical repair did not occur. A postoperative cerebrospinal fluid (CSF) rhinorrhea occurred in one pituitary macroadenoma, and no infection was observed in any case. From the authors' experience, advantages of the silicone plate are its simplicity to shape for any size of defects, and the easy detectability of the previous bone window at reoperation.

Mitochondria determine the survival and death in apoptosis by an endogenous neurotoxin, N-methyl(R)salsolinol, and neuroprotection by propargylamines

In neurodegenerative disorders, such as Parkinson's disease, selective neuronal death characterizes clinical signs and symptoms. Recently apoptosis was reported to be a common type of cell death in some disorders, and well-controlled apoptotic cascade is proposed to be a target of neuroprotective therapy. In our studies to find endogenous neurotoxins as a pathogenic factor in Parkinson's disease, dopamine-derived N-methyl(R)salsolinol was found to induce apoptosis in dopamine neurons of rat models of Parkinson's disease. In human dopaminergic SH-SY5Y cells, apoptosis was initiated by decline in mitochondrial membrane potential, and anti-apoptotic Bcl-2 family protein regulated apoptotic signal transduction. In addition, a series of propargylamines were found to prevent apoptosis through stabilization of mitochondrial membrane potential, which also involved Bcl-2. The role of mitochondria and the involvement of Bcl-2 in apoptosis and neuroprotection were clearly demonstrated using isolated mitochondria. These results indicate that mitochondria are the site to determine the cell death induced by neurotoxins and also the neuroprotection by anti-apoptotic propargylamines.

Selective nitration of mitochondrial complex I by peroxynitrite: involvement in mitochondria dysfunction and cell death of dopaminergic SH-SY5Y cells

3-Nitrotyrosine (3-NT) is a specific marker of protein nitration by peroxynitrite (ONOO-) produced from nitric oxide and superoxide. Increase in 3-NT containing protein (3-NT protein) was reported in brains from patients with some neurodegenerative disorders and aging. In this paper, intracellular localization of 3-NT protein was examined in dopaminergic SH-SY5Y cells using the selective antibody against protein-bound 3-NT. 3-NT protein was detected in plasma membrane/nucleus and mitochondria fractions, and interestingly in polypeptide composition of mitochondrial complex I. ONOO--generating SIN-1 induced apoptotic cell death with concomitant increase in 3-NT protein and reduction in mitochondrial ATP synthesis. In addition, an inhibitor of proteasomes, carbobenzoxy-L-isoleucyl-gamma-t-butyl-L-glutamyl-L-alanyl-L-leucinal, enhanced the effects of ONOO-. These results suggest that ONOO- may induce mitochondrial dysfunction and cell death in neurons through nitration of mitochondrial complex I subunits.

Structure-activity relationship studies of isoquinolinone type anticancer agent

Substituted isoquinolin-1-ones (1) were synthesized to test their in vitro anticancer activity. 3-Biphenyl-N-methylisoquinolin-1-one (7) showed the most potent anticancer activity against five different human cancer cell lines.

Expression of vascular endothelial growth factor and its receptors Flt-1 and KDR/Flk-1 in chronic cyclosporine nephrotoxicity

BACKGROUND

Vascular endothelial growth factor (VEGF) is an endothelial cell mitogen involved in angiogenesis, wound healing, and inflammation.

METHODS

Rats placed on low salt diet (LSD) or normal salt diet (NSD) were treated with cyclosporine (CsA) or vehicle (VH) and killed at 7 or 28 days. We studied the expression of VEGF and its receptors Flt-1 and KDR/Flk-1 mRNA by Northern and that of VEGF protein by Western blot.

RESULTS

CsA induced VEGF mRNA and protein expressions at 7 and 28 days in LSD rats. At 7 days, CsA up-regulated the expression of Flt-1 and KDR/Flk-1 receptors; however, at 28 days, Flt-1 remained unchanged whereas KDR/Flk-1 expression declined. In NSD rats, in which the lesion did not develop, the expression of VEGF and its receptors remained similar to control.

CONCLUSIONS

What causes VEGF to be up-regulated remains unclear. Further studies are needed to study the role of hypoxia and other cytokines in relation to VEGF in this model.

[Study on telomerase activity and its clinical value in human non small cell lung cancer]

OBJECTIVE

To investigate telomerase activity and its clinical value in human non small cell lung cancer.

METHODS

Using the method of TRAP-PCR-ELISA, we measured telomerase activity in human non small cell lung cancerous, adjacent, lung benign lesion, and normal lung tissues.

RESULTS

The positive rate of telomerase activity was 75%(27/36) in lung cancerous tissues; 6.25%(2/32) in adjacent tissues; 11.1%(1/9) in lung benign lesion tissues; and 0%(0/9) in normal lung tissues. There was no significant difference in telomerase activity among the pathological type, the degree of tissue differentiation, the size of tumor, lymph node metastasis, and clinical stage in the patients with lung cancer.

CONCLUSION

The telomerase activity may become an important molecular marker in the diagnosis and differential diagnosis of human non small cell lung cancer.

Voltammetric determination of cadmium(II) using a chemically modified electrode

An 1-(pyridylazo)-2-naphthol modified glassy carbon electrode has been investigated as sensor for the measurement of trace levels of Cd2+. Cd2+ is deposited on the surface of a PAN modified glassy carbon electrode at -1.10 V (vs. SCE) via forming Cd2+-PAN and subsequent reduction at the electrode. In the following step, Cd-PAN is oxidized, and voltammograms are recorded by scanning the potential in a positive direction. Calibration plots were found to be linear in the range 2 x 10(-8) mol/L to 8 x 10(-7) mol/L. The detection limit was 5 x 10(-10) mol/L, and the coefficient of variation, determined on one single electrode at a concentration of 5 x 10(-7) mol/L, was calculated to be 3.2% (n = 5). Using this new kind of modified electrode, trace levels of Cd(II) in water samples were determined; the average recovery was calculated to be 98.78%.

[Telomerase activity in bladder cancer tissues]

OBJECTIVE

To study the correlation between telomerase and bladder cancer.

METHODS

The telomerase activity was detected by telomerase PCR ELISA in 41 cases of bladder cancer tissues and 23 cases of non-cancerous bladder tissues.

RESULTS

The telomerase activity was positive in 34 cases of bladder cancer tissues (82.9%) and 1 case of non-cancerous tissues (4.3%); the difference of positive rate was significant (P < 0.01).

CONCLUSIONS

Telomerase activity is related with bladder cancer closely; telomerase activation may be an important molecular step in the initiation and development of bladder cancer; telomerase may be an excellent molecular biomarker in finding bladder cancer at an early stage and in postoperative following-up.

A novel procedure for pre-embedding double immunogold-silver labeling at the ultrastructural level

Pre-embedding double immunogold-silver labeling using two ultrasmall gold conjugates has not been attempted previously because a means of distinguishing labels by conjugates of identical sizes was lacking. This study investigated the feasibility of creating a particle size segregation between two ultrasmall gold conjugates through sequential immunogold incubations and silver enhancements. Two primary antibodies, mouse anti-synaptophysin and rabbit anti-glial fibrillary acidic protein (GFAP), were used in the model system. Differentiation of the double labeling was achieved by incubating with one ultrasmall gold conjugate, followed by silver enhancement, and then incubating with the second ultrasmall gold conjugate, followed by additional silver enhancement. This resulted in two groups of silver-enhanced particles: smaller particles enhanced once and larger particles enhanced twice. Electron microscopic examination revealed two readily distinguished populations of gold-silver particles within the appropriate structures, with very little size overlap. The quality of the ultrastructure permitted identification of most subcellular organelles. This procedure provides for the first time a pre-embedding immunogold-silver labeling protocol that allows the precise subcellular co-localization of multiple antigens.

Alteration of a single amino acid changes the substrate specificity of dihydroflavonol 4-reductase

Many plant species exhibit a reduced range of flower colors due to the lack of an essential gene or to the substrate specificity of a biosynthetic enzyme. Petunia does not produce orange flowers because dihydroflavonol 4-reductase (DFR) from this species, an enzyme involved in anthocyanin biosynthesis, inefficiently reduces dihydrokaempferol, the precursor to orange pelargonidin-type anthocyanins. The substrate specificity of DFR, however, has not been investigated at the molecular level. By analyzing chimeric DFRs of Petunia and Gerbera, we identified a region that determines the substrate specificity of DFR. Furthermore, by changing a single amino acid in this presumed substrate-binding region, we developed a DFR enzyme that preferentially reduces dihydrokaempferol. Our results imply that the substrate specificity of DFR can be altered by minor changes in DFR.

Stability of the smectic quantum hall state: a quantitative study

We present an effective elastic theory which quantitatively describes the stripe phase of the two-dimensional electron gas in high Landau levels ( N>/=2). The dynamical matrix is obtained with remarkably high precision using the time-dependent Hartree-Fock approximation. A renormalization group analysis shows that at T = 0, as the partial filling factor Deltanu identical withnu- left floornu right floor moves away from 1/2, the anisotropic conducting state may undergo quantum phase transitions: stripes may get pinned along their conducting direction by disorder, or may lock into one another to form a crystal. The transitions should be reflected in the temperature dependence of the dissipative conductivity.

[Telomerase activity of peripheral blood mononuclear cells in patients with acquired immune dysfunction]

OBJECTIVE

To investigate telomerase activity of peripheral blood mononuclear cells (PBMC) in patients with acquired immune dysfunction.

METHODS

Telomerase activity of peripheral PBMC isolated from 4 groups including healthy subjects (17), chronic hepatitis B patients (14), diabetic patients (8) and chronic renal failure patients (8) was assayed with PCR-ELISA.

RESULTS

(1) Telomerase activity was detectable at low levels in resting PBMC of all the 4 groups. It increased obviously after in vitro phytohemagglutinin (PHA) stimulation; (2) Telomerase activity of the resting PBMC in chronic hepatitis B patients was significantly lower than that in normal subjects, and was upregulated to the same level in the both groups after PHA stimulation; (3) No effect of recombinant human interleukin-12 on telomerase activity of activated T lymphocytes was found.

CONCLUSIONS

PBMC may express telomerase activity and the decreased telomerase activity of PBMC in patients with chronic hepatitis B may partially be responsible for immune dysfunction in these patients.

Effect of nitric oxide modulation on TGF-beta1 and matrix proteins in chronic cyclosporine nephrotoxicity

BACKGROUND

Chronic cyclosporine (CsA) nephrotoxicity is characterized by interstitial fibrosis and afferent arteriolar hyalinosis. L-arginine (L-Arg), the substrate for nitric oxide (NO) synthase and N-nitro-L-arginine-methyl ester (L-NAME), the NO synthase inhibitor, were shown to modulate acute CsA nephrotoxicity. However, the mechanism of fibrosis in chronic CsA nephrotoxicity remains unclear. Thus, we examined the effect of NO modulation on fibrosis and the expression of transforming growth factor-beta1 (TGF-beta1) and matrix proteins in chronic CsA nephrotoxicity.

METHODS

Rats were administered CsA (7.5 mg/kg), CsA + L-Arg (1.7 g/kg), CsA + L-NAME (3.5 mg/kg), vehicle (VH), VH + L-Arg, and VH + L-NAME, and were sacrificed at 7 or 28 days. NO production, physiologic parameters, and histology were studied in addition to the mRNA expression of TGF-beta1, plasminogen activator inhibitor-1 (PAI-1) and the matrix proteins biglycan and collagens type I and IV by Northern and the protein expression of PAI-1 and fibronectin by enzyme-linked immunosorbent assay.

RESULTS

While L-NAME strikingly reduced NO biosynthesis and worsened the glomerular filtration rate and CsA-induced fibrosis, L-Arg had the opposite beneficial effect. In addition, the CsA-induced up-regulated expression of TGF-beta1, PAI-1, and the matrix proteins biglycan, fibronectin, and collagen I was significantly increased with L-NAME and strikingly improved with L-Arg. Collagen IV expression was not affected. Also, NO modulation did not affect VH-treated rats.

CONCLUSIONS

Chronic CsA nephrotoxicity can be aggravated by NO blockade and ameliorated by NO enhancement, suggesting that NO maintains a protective function. NO modulation was associated with a change in TGF-beta1 expression, which, in turn, was associated with alterations in matrix deposition and matrix degradation through its effect on PAI-1.

Telomerase activity of peripheral blood lymphocytes in patients with chronic hepatitis B

Chronic hepatitis B is the immunocompromising condition. The decrease of lymphocyte telomerase is linked to immunosenescence in hosts. To know whether telomerase activity of lymphocytes is involved in immunopathogenesis in patients with chronic hepatitis B, telomerase activity of peripheral lymphocytes was determined in such patients. The results showed that telomerase activity in resting peripheral lymphocytes of healthy subjects was detectable at low level, and obviously increased (P<0.001) after stimulation in vitro with phytohaemagglutinin (PHA). Telomerase activity of lymphocytes decreased with age in both groups with or without PHA stimulation. Telomerase activity of resting lymphocytes in patients with chronic hepatitis B was also observed at detectable level and markedly upregulated after PHA stimulation. The decreased telomerase activity of resting lymphocytes was found in patients with chronic hepatitis B (n=14, 0.32+/-0.27) compared to that in healthy subjects (n=17, 0. 52+/-0.28; P<0.05). However, there was no difference present between these two groups in telomerase activity of activated lymphocytes with PHA. In addition, no effect of recombinant human interleukin-12 (rhIL-12) on telomerase expression was observed in either the patient group or the healthy group. We concluded that the decreased telomerase activity of lymphocytes in chronic hepatitis B patients is present, which may be partly responsible for immunosuppressive condition in such patients.