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.

Effect of IL-12 on T-cell immune responses in patients with chronic HCV infection

As the host's immune responses may determine the outcome of hepatitis C virus (HCV) infection, and interleukin (IL)-12 plays an essential role in host defense against infectious diseases, we studied the antigen-specific and non-specific cellular immune responses in patients with chronic HCV infection. A proliferative response to phytohemagglutinin (PHA) was found in all 20 patients. Of the 20, 8 (40%) displayed a lymphocyte proliferation in response to HCV antigen c22, 2 (10%) to c33, 6 (30%) to c100-3, and 1 (5%) to NS5. The addition of rhIL-12 to cultures of peripheral blood mononuclear cells (PBMC) stimulated with PHA significantly enhanced the proliferative responses in normal controls as well as in HCV-infected subjects. The increased proliferation was also observed in HCV-infected patients when PBMC were co-cultured with HCV antigens c22 and c100-3 in the presence of rhIL-12. The production of interferon gamma (IFNgamma), IL-2, IL-4 and IL-10 was observed in 7 (58.3%), 5 (41.7%), 3 (25.0%) and 5 (41.7%) HCV-infected individuals stimulated with c22, and in 4 (33.3%), 2 (16.7%), 2 (16.7%) and 2 (16.7%) with c100-3, respectively. All HCV-infected individuals had increased production of cytokines IFNgamma, IL-2, IL-4 and IL-10 in supernatants of PBMC after stimulation with PHA. IL-12 significantly augmented Th1 cytokine production in HCV-infected individuals stimulated with PHA and with HCV antigens. In conclusion, deficient cellular immune responses are present in HCV-infected patients and IL-12 can enhance the immune responses in these patients.

Localization of M(2) muscarinic acetylcholine receptor protein in cholinergic and non-cholinergic terminals in rat hippocampus

The muscarinic receptor family (M(1)-M(4)) mediates cholinergic modulation of hippocampal transmission. Pharmacological and physiological studies have indicated that a presynaptic receptor on cholinergic terminals plays a key role in regulating ACh release, although the molecular identity of this subtype is uncertain. In this study, the localization of the M(2) receptor is described in detail for the pyramidal cell layer in the CAl region of the hippocampus. Electron microscopic analysis of M(2) immunoreactivity in this area revealed mainly presynaptic expression of this subtype. Double-labeling experiments using antibodies to M(2) and to the vesicular acetylcholine transporter, a novel, specific marker of cholinergic terminals, were used to investigate the nature of these presynaptic receptors. These studies have revealed that M(2) is located in cholinergic and non-cholinergic terminals. This is the first direct anatomical evidence that suggests that M(2) may indeed function as a cholinergic autoreceptor in the hippocampus. The distribution of the M(2) receptor in non-cholinergic terminals also suggests functional roles for M(2) as a presynaptic heteroreceptor.

Morphogenetic proteins SpoVID and SafA form a complex during assembly of the Bacillus subtilis spore coat

During endospore formation in Bacillus subtilis, over two dozen polypeptides are assembled into a multilayered structure known as the spore coat, which protects the cortex peptidoglycan (PG) and permits efficient germination. In the initial stages of coat assembly a protein known as CotE forms a ring around the forespore. A second morphogenetic protein, SpoVID, is required for maintenance of the CotE ring during the later stages, when most of proteins are assembled into the coat. Here, we report on a protein that appears to associate with SpoVID during the early stage of coat assembly. This protein, which we call SafA for SpoVID-associated factor A, is encoded by a locus previously known as yrbA. We confirmed the results of a previous study that showed safA mutant spores have defective coats which are missing several proteins. We have extended these studies with the finding that SafA and SpoVID were coimmunoprecipitated by anti-SafA or anti-SpoVID antiserum from whole-cell extracts 3 and 4 h after the onset of sporulation. Therefore, SafA may associate with SpoVID during the early stage of coat assembly. We used immunogold electron microscopy to localize SafA and found it in the cortex, near the interface with the coat in mature spores. SafA appears to have a modular design. The C-terminal region of SafA is similar to those of several inner spore coat proteins. The N-terminal region contains a sequence that is conserved among proteins that associate with the cell wall. This motif in the N-terminal region may target SafA to the PG-containing regions of the developing spore.

Glycine receptor (gephyrin) immunoreactivity is present on cholinergic neurons in the dorsal vagal complex

We previously demonstrated that microinjection of exogenous glycine into the nucleus tractus solitarii of anesthetized rats elicits responses that are qualitatively like those elicited by microinjection of acetylcholine at the same site. The responses to glycine, like those to acetylcholine, are blocked by administration of a muscarinic receptor antagonist and prolonged by administration of an acetylcholinesterase inhibitor. Furthermore, glycine leads to release of acetylcholine from the nucleus tractus solitarii and surrounding dorsal vagal complex. An anatomical framework for interactions between glycinergic and cholinergic neurons was established by studies that identified glycine terminals and receptors in the dorsal vagal complex. The current study investigated the relationship between glycine receptors and neuronal elements that were immunoreactive for choline acetyltransferase in the dorsal vagal complex. Neurons that were immunoreactive for choline acetyltransferase were located in the dorsal motor nucleus of the vagus, hypoglossal nucleus and nucleus ambiguus, and stained cells were also present in medial, intermediate, and ventrolateral subnuclei of the nucleus tractus solitarii. We found that glycine receptors, immunolabeled with an antibody to gephyrin, were present on cholinergic dendrites in the nucleus tractus solitarii. Gephyrin immunoreactivity was also present on dendrites that did not stain for choline acetyltransferase. These data further support the contribution of cholinergic neurons in mediating cardiovascular responses to glycine in the nucleus tractus solitarii.

Long glutamine tracts cause nuclear localization of a novel form of huntingtin in medium spiny striatal neurons in HdhQ92 and HdhQ111 knock-in mice

Huntington's disease (HD) is caused by an expanded N-terminal glutamine tract that endows huntingtin with a striatal-selective structural property ultimately toxic to medium spiny neurons. In precise genetic models of juvenile HD, HdhQ92 and HdhQ111 knock-in mice, long polyglutamine segments change huntingtin's physical properties, producing HD-like in vivo correlates in the striatum, including nuclear localization of a version of the full-length protein predominant in medium spiny neurons, and subsequent formation of N-terminal inclusions and insoluble aggregate. These changes show glutamine length dependence and dominant inheritance with recruitment of wild-type protein, critical features of the altered HD property that strongly implicate them in the HD disease process and that suggest alternative pathogenic scenarios: the effect of the glutamine tract may act by altering interaction with a critical cellular constituent or by depleting a form of huntingtin essential to medium spiny striatal neurons.

Phylogenetic and phenotypic diversity of 4-chlorobenzoate-degrading bacteria isolated from soils

Twenty numerically dominant 4-chlorobenzoate (4-CBA)-degrading bacteria were isolated from agricultural soils. The isolates were able to utilize 4-CBA as a sole source of carbon and energy. A total of 65% of the isolates was identified to the species level by fatty acid methyl ester (FAME) analysis, and the isolates were strains of Micrococcus, Pseudomonas, Oerskovia, Cellulomonas, and Arthrobacter species. The chromosomal DNA patterns of the isolates obtained by polymerase chain reaction (PCR) amplification of repetitive extragenic palindromic (REP) sequences were distinct from each other. Most of the isolates grew rapidly in 4-CBA medium, but their substrate utilization capabilities were generally restricted. Plasmid DNAs were detected from 55% of the isolates, and one strain, HR7, was shown to have self-transmissible, 4-CBA degradative plasmids. 4-CBA degradative enzymes were inducible by the presence of 4-CBA and most of the isolates appeared to mineralize it through 4-hydroxybenzoate rather than 4-chlorocatechol.

Expression of apoptosis regulatory genes in chronic cyclosporine nephrotoxicity favors apoptosis

Expression of apoptosis regulatory genes in chronic cyclosporine nephrotoxicity favors apoptosis.

BACKGROUND

Chronic cyclosporine (CsA) nephrotoxicity is characterized by interstitial fibrosis, tubular dropout, and loss of cellularity in areas of fibrosis. Apoptosis was found to play a role in CsA-induced fibrosis. We evaluated the role of the death genes p53, Bax, and Fas-L (ligand), survival gene Bcl-2, interleukin-converting enzyme (ICE), and caspase-3.

METHODS

Salt-depleted rats were administered CsA 15 mg/kg/day or vehicle (VH) and were sacrificed at 7 or 28 days. Apoptosis was detected by TdT-mediated dUTP-biotin nick end labeling assay. p53 and Bax expressions were evaluated by Northern and Western blot analysis. Fas-L and Bcl-2 expressions were evaluated by immunofluorescence. In addition to ICE mRNA, caspase-3 enzymatic activity was assayed.

RESULTS

Although no differences were seen at one week, apoptosis-positive cells increased with CsA at four weeks (P < 0.05) and correlated with tubular atrophy and interstitial fibrosis (r = 0.8, P < 0.05). CsA induced the expression of p53 (P < 0.05) and Bax (P < 0.01) and decreased that of Bcl-2 (P < 0.05). CsA up-regulated Fas-L expression (P < 0.001). ICE mRNA and caspase-3 activity were also increased (P < 0.01). The changes occurred as early as one week and remained statistically significant at four weeks.

CONCLUSIONS

Specific apoptotic genes are increased in chronic CsA nephrotoxicity. The balance favors the induction of apoptosis. Increased apoptosis could explain the tubular dropout and loss of cellularity with fibrosis. This then may impair the ability of the tubulointerstitium to remodel. Apoptosis could also contribute to some of CsA immunosuppressive effects on activated lymphocytes.

[A study on hemostatic and immunological actions of fresh and dry Dihuang]

OBJECTIVE

To investigate the difference between fresh and dry Dihuang (Radix Rehmanniae) in hemostatic and immunological actions.

METHODS

The hemostatic action was assessed in aspirin-treated mice; immunological action was assessed by phagocytosis of macrophages in dexamethasone-treated mice; and Con A-induced mitogenesis and LPS-induced alkaline phosphatase activity of splenocytes were determined in thyroxin-treated mice.

RESULT

The blood clotting in mice induced by aspirin was inhibited by oral administrations of juice decoction of fresh Dihuang or decoction of dry Dihuang alike. The action of fresh Dihuang juice was stronger than that of dry Dihuang decoction. Oral administrarion of fresh Dihuang juice or decoction for 10 days enhanced LPS-induced alkaline phosphatase activity of splenocytes in thyroxin-treated mice. The juice also enhanced Con A-induced splenocyte mitogenesis. The action of dry Dihuang decoction was weaker than that of fresh juice in increasing LPS-induced alkaline phosphatase activity.

CONCLUSION

It is recommended to follow the tradition of using fresh Dihuang juice or decoction to treat some diseases such as hemorrhagenic troubles.

Phytochrome signalling is mediated through nucleoside diphosphate kinase 2

Because plants are sessile, they have developed intricate strategies to adapt to changing environmental variables, including light. Their growth and development, from germination to flowering, is critically influenced by light, particularly at red (660 nm) and far-red (730 nm) wavelengths. Higher plants perceive red and far-red light by means of specific light sensors called phytochromes(A-E). However, very little is known about how light signals are transduced to elicit responses in plants. Here we report that nucleoside diphosphate kinase 2 (NDPK2) is an upstream component in the phytochrome signalling pathway in the plant Arabidopsis thaliana. In animal and human cells, NDPK acts as a tumour suppressor. We show that recombinant NDPK2 in Arabidopsis preferentially binds to the red-light-activated form of phytochrome in vitro and that this interaction increases the activity of recombinant NDPK2. Furthermore, a mutant lacking NDPK2 showed a partial defect in responses to both red and farred light, including cotyledon opening and greening. These results indicate that NDPK2 is a positive signalling component of the phytochrome-mediated light-signal-transduction pathway in Arabidopsis.