RXR beta: a coregulator that enhances binding of retinoic acid, thyroid hormone, and vitamin D receptors to their cognate response elements

The retinoic acid receptor (RAR) requires coregulators to bind effectively to response elements in target genes. A strategy of sequential screening of expression libraries with a retinoic acid response element and RAR identified a cDNA encoding a coregulator highly related to RXR alpha. This protein, termed RXR beta, forms heterodimers with RAR, preferentially increasing its DNA binding and transcriptional activity on promoters containing retinoic acid, but not thyroid hormone or vitamin D, response elements. Remarkably, RXR beta also heterodimerizes with the thyroid hormone and vitamin D receptors, increasing both DNA binding and transcriptional function on their respective response elements. RXR alpha also forms heterodimers with these receptors. These observations suggest that retinoid X receptors meet the criteria for biochemically characterized cellular coregulators and serve to selectively target the high affinity binding of retinoic acid, thyroid hormone, and vitamin D receptors to their cognate DNA response elements.

ABFs, a family of ABA-responsive element binding factors

Abscisic acid (ABA) plays an important role in environmental stress responses of higher plants during vegetative growth. One of the ABA-mediated responses is the induced expression of a large number of genes, which is mediated by cis-regulatory elements known as abscisic acid-responsive elements (ABREs). Although a number of ABRE binding transcription factors have been known, they are not specifically from vegetative tissues under induced conditions. Considering the tissue specificity of ABA signaling pathways, factors mediating ABA-dependent stress responses during vegetative growth phase may thus have been unidentified so far. Here, we report a family of ABRE binding factors isolated from young Arabidopsis plants under stress conditions. The factors, isolated by a yeast one-hybrid system using a prototypical ABRE and named as ABFs (ABRE binding factors) belong to a distinct subfamily of bZIP proteins. Binding site selection assay performed with one ABF showed that its preferred binding site is the strong ABRE, CACGTGGC. ABFs can transactivate an ABRE-containing reporter gene in yeast. Expression of ABFs is induced by ABA and various stress treatments, whereas their induction patterns are different from one another. Thus, a new family of ABRE binding factors indeed exists that have the potential to activate a large number of ABA/stress-responsive genes in Arabidopsis.

Temporal aspects of DNA and RNA synthesis during human immunodeficiency virus infection: evidence for differential gene expression

The kinetics of retroviral DNA and RNA synthesis are parameters vital to understanding viral growth, especially for human immunodeficiency virus (HIV), which encodes several of its own regulatory genes. We have established a single-cycle growth condition for HIV in H9 cells, a human CD4+ lymphocyte line. The full-length viral linear DNA is first detectable by 4 h postinfection. During a one-step growth of HIV, amounts of viral DNA gradually increase until 8 to 12 h postinfection and then decrease. The copy number of unintegrated viral DNA is not extraordinarily high even at its peak. Most strikingly, there is a temporal program of RNA accumulation: the earliest RNA is greatly enriched in the 2-kilobase subgenomic mRNA species, while the level of 9.2-kilobase RNA which is both genomic RNA and mRNA remains low until after 24 h of infection. Virus production begins at about 24 h postinfection. Thus, viral DNA synthesis is as rapid as for other retroviruses, but viral RNA synthesis involves temporal alteration in the species that accumulate, presumably as a consequence of viral regulatory genes.

Fluorous synthesis: a fluorous-phase strategy for improving separation efficiency in organic synthesis

Recovery and purification difficulties can limit the yield and utility of otherwise successful organic synthesis strategies. A "fluorous synthesis" approach is outlined in which organic molecules are rendered soluble in fluorocarbon solvents by attachment of a suitable fluorocarbon group. Fluorocarbon solvents are usually immiscible in organic solutions, and fluorous molecules partition out of an organic phase and into a fluorous phase in a standard liquid-liquid extraction. Simple yet substantive separations of organic reaction mixtures are achieved without resorting to chromatography. Because fluorous synthesis combines in many respects the favorable purification features of solid-phase synthesis with the favorable reaction, identification, and analysis features of traditional organic synthesis, it should prove valuable in the automated synthesis of libraries of individual pure organic compounds.

Effects of naturally occurring flavonoids on nitric oxide production in the macrophage cell line RAW 264.7 and their structure-activity relationships

Flavonoids affect the inflammatory process of the mammalian system and possess anti-inflammatory as well as immunomodulatory activities in vitro and in vivo. Since nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) is one of the inflammatory mediators, the effects of various naturally occurring flavonoids on NO production in LPS-activated RAW 264.7 cells were evaluated in vitro. Flavonoids such as apigenin, wogonin, luteolin, tectorigenin, and quercetin inhibited NO production, as measured by nitrite formation at 10-100 microM. The most active among 26 flavonoid derivatives tested were apigenin, wogonin, and luteolin, having IC50 values of 23, 17, and 27 microM, respectively, while AMT, a synthetic selective iNOS inhibitor, had an IC50 value of 0.09 microM. In contrast, flavanones, such as naringenin, and flavonoid glycosides, such as apiin, did not demonstrate significant inhibition up to 100 microM. These results clearly indicated that a C-2,3 double bond might be important, and that the potency of inhibition depended upon the substitution patterns of the flavonoid molecules. The inhibitory activity of flavonoids was not due to direct inhibition of iNOS enzyme activity because they did not reasonably inhibit iNOS activity, as measured by [3H]citrulline formation from [3H]arginine, up to 100 microM. In contrast, wogonin and luteolin concentration-dependently reduced iNOS enzyme expression, when measured by western blotting, at 10-100 microM. All these results clearly demonstrated that certain flavonoids inhibit NO production in lipopolysaccharide-activated RAW 264.7 cells, and their inhibitory activity might be due to reduction of iNOS enzyme expression.

Destruction of Myc by ubiquitin-mediated proteolysis: cancer-associated and transforming mutations stabilize Myc

The human proto-oncogene c-myc encodes a highly unstable transcription factor that promotes cell proliferation. Although the extreme instability of Myc plays an important role in preventing its accumulation in normal cells, little is known about how Myc is targeted for rapid destruction. Here, we have investigated mechanisms regulating the stability of Myc. We show that Myc is destroyed by ubiquitin-mediated proteolysis, and define two elements in Myc that oppositely regulate its stability: a transcriptional activation domain that promotes Myc destruction, and a region required for association with the POZ domain protein Miz-1 that stabilizes Myc. We also show that Myc is stabilized by cancer-associated and transforming mutations within its transcriptional activation domain. Our data reveal a complex network of interactions regulating Myc destruction, and imply that enhanced protein stability contributes to oncogenic transformation by mutant Myc proteins.

Maternal obesity and risk of cesarean delivery: a meta-analysis

Despite numerous studies reporting an increased risk of cesarean delivery among overweight or obese compared with normal weight women, the magnitude of the association remains uncertain. Therefore, we conducted a meta-analysis of the current literature to provide a quantitative estimate of this association. We identified studies from three sources: (i) a PubMed search of relevant articles published between January 1980 and September 2005; (ii) reference lists of publications selected from the search; and (iii) reference lists of review articles published between 2000 and 2005. We included cohort designed studies that reported obesity measures reflecting pregnancy body mass, had a normal weight comparison group, and presented data allowing a quantitative measurement of risk. We used a Bayesian random effects model to perform the meta-analysis and meta-regression. Thirty-three studies were included. The unadjusted odd ratios of a cesarean delivery were 1.46 [95% confidence interval (CI): 1.34-1.60], 2.05 (95% CI: 1.86-2.27) and 2.89 (95% CI: 2.28-3.79) among overweight, obese and severely obese women, respectively, compared with normal weight pregnant women. The meta-regression found no evidence that these estimates were affected by selected study characteristics. Our findings provide a quantitative estimate of the risk of cesarean delivery associated with high maternal body mass.

A phase III randomized study of 5-fluorouracil and cisplatin versus 5-fluorouracil, doxorubicin, and mitomycin C versus 5-fluorouracil alone in the treatment of advanced gastric cancer

BACKGROUND

With the introduction of cisplatin-containing regimens in the treatment of advanced gastric cancer, promising clinical results have been reported. A 61.5% response rate was observed with a combination of 5-fluorouracil (5-FU) infusion and bolus cisplatin; however, the superiority of cisplatin-containing regimens to other regimens has not been clearly verified in any randomized controlled studies. A prospective, randomized study of 5-FU and cisplatin (FP) versus 5-FU, doxorubicin, and mitomycin C (FAM) versus 5-FU alone (FU) in previously untreated patients with advanced gastric cancer is reported.

METHODS

A total of 324 patients were entered into the trial and 295 patients (103 for FP, 98 for FAM, 94 for FU) were evaluable. The patients were randomized to receive FP, FAM, or FU after stratifying by the following factors: performance status, presence of measurable disease, and resection of the primary tumor.

RESULTS

The overall response rate for patients with measurable disease in the FP arm was significantly higher than in the FAM and FU arms (51% for FP; 25% for FAM; 26% for FU). The durations of response for each arm, however, were not significantly different. Even though the median time to progression for the FP arm (21.8 weeks) was longer than that for the FAM arm (12 weeks; P < 0.05) and for the FU arm (9.1 weeks; P < 0.005), there was no statistical difference in overall survival among the three arms. Toxicity for all three regimens was moderate and consisted primarily of myelosuppression, nausea, vomiting, and alopecia.

CONCLUSIONS

Although the FP regimen showed a significantly higher response rate and a longer time to progression than the FAM or FU regimens, a survival benefit was not observed.

The prediction of abdominal visceral fat level from body composition and anthropometry: ROC analysis

OBJECTIVE

To evaluate the merit of body mass index (BMI), % body fat, waist circumference and waist-to-hip ratio as predictors of abdominal visceral fat (AVF) level.

DESIGN

Cross-sectional measurements obtained from 458 female and 331 male subjects of French Canadian descent with an age range from 18-72 y.

MEASUREMENTS

AVF level was assessed by computed tomography. BMI was calculated as weight (in kg) divided by stature2 (in m), body density was derived from underwater weighing and % body fat was computed from the estimate of body density with the Siri equation. Waist-to-hip ratio was calculated as waist circumference divided by hip circumference. Receiver operating characteristic (ROC) curves were used to identify the optimal cut-off points.

RESULTS

In younger women (< 40 y, n = 258), waist-to-hip ratio was the poorest predictor of AVF level with areas under the ROC curves (Az) ranging from 0.684-0.716, sensitivity (Sen) from 63.3-68.8% and specificity (Spe) from 64.0-67.5%, whereas the Az, Sen and Spe for other predictors ranged from 0.924-0.983, 87.0-96.8, and 83.4-92.7, respectively. The same trend was observed in older (> or = 40 y, n = 200) women, although differences between waist-to-hip ratio and other predictors were less pronounced. In older men, waist circumference was the best overall predictor (Az from 0.88-0.92), whereas BMI showed the lowest Az values (0.831-0.875, P < or = 0.001 vs waist circumference). In younger men, BMI had the smallest Az (P < 0.007 vs others) with the lowest AVF cut-off point (100 cm2). However, with higher AVF cut-offs the differences were not significant.

CONCLUSION

Waist circumference is the best overall predictor of abdominal visceral obesity, whereas in women waist-to-hip ratio is a poor indicator of AVF and its use as a surrogate measure of visceral fat should be avoided.

Methoxy poly(ethylene glycol) and epsilon-caprolactone amphiphilic block copolymeric micelle containing indomethacin. II. Micelle formation and drug release behaviours

Amphiphilic diblock copolymer composed of methoxy poly(ethylene glycol) and epsilon-caprolactone (epsilon-CL) was prepared by polymerization of epsilon-CL initiated with MePEG. MePEG/epsilon-CL block copolymeric micelles containing indomethacin (IMC) were prepared by a dialysis method and evaluated as a novel drug carrier. The size of micelle formed was less than 200 nm, and the size distribution of the micelle showed a narrow and monodisperse unimodal pattern. Also, the micelles formed by a dialysis method exhibited spherical structures. The indomethacin content in nanospheres was about 42.2%, for those prepared using copolymer, having molecular weight of about 12,000 and polymer/IMC weight ratio of 1/1. A release rate of indomethacin from nanospheres was slow, and thus the release continued over 15 days. As the molecular weights of the copolymer and the amount of drug entrapped increased, the release rate decreased. These results indicated that the drug-loaded nanospheres could be useful as a novel drug carrier in injectable delivery systems for hydrophobic drugs.

The phosphatidylinositol 3-kinase, p38, and extracellular signal-regulated kinase pathways are involved in osteoclast differentiation

Phosphatidylinositol 3-kinase (PI 3-kinase) and mitogen-activated protein kinases (MAPKs) have been implicated in diverse cellular functions, including proliferation, migration, and survival. In this study, we examined the involvement of these kinases in osteoclast differentiation by employing specific inhibitors of the kinases. The osteoclast differentiation was assessed in three different culture systems: a coculture of mouse bone marrow cells with mouse calvarial osteoblasts, a mouse bone marrow cell culture in the presence of receptor activator of NF-kappaB ligand (RANKL) and macrophage-colony stimulating factor (M-CSF), and a culture of bone-resident osteoclast precursor cells driven by RANKL and M-CSF. LY294002, a specific inhibitor of PI 3-kinase, potently inhibited osteoclast differentiation in all culture systems when assessed by both tartrate-resistant acid phosphatase (TRAP) staining and dentine resorption assays. Inhibition of p38 MAPK by SB202190 resulted in a strong suppression in the exogenous RANKL dependent mouse bone marrow and bone resident precursor cell cultures. Another MAPK pathway inhibitor (PD98059), which blocks the activation of extracellular signal-regulated kinase (ERK) by inhibiting the upstream kinase MAPK-ERK kinase (MEK) 1, exerted an inhibitory effect on osteoclast differentiation only at the highest concentration tested (30 micromol/L) in many cases. Whether the signaling pathways involving these kinases are activated by RANKL was also examined. The RANKL-stimulated phosphorylation of Akt, a downstream target of PI 3-kinase, and that of ERK were observed. RANKL also stimulated the activity of p38. These results suggest that PI 3 kinase, p38, and ERK play roles in osteoclast differentiation, at least in part, by participating in RANKL signaling.

Intravenous calcitriol regresses myocardial hypertrophy in hemodialysis patients with secondary hyperparathyroidism

To evaluate the response of circulating intact parathyroid hormone (iPTH) on myocardial hypertrophy in hemodialysis (HD) patients with secondary hyperparathyroidism (SHPT), echocardiographic and neurohormonal assessments were performed over a 15-week period in 15 HD patients with SHPT before and after calcitriol treatment and 10 HD control patients with SHPT not receiving calcitriol therapy. We prospectively studied a group of 15 patients with significantly elevated iPTH levels (iPTH >450 pg/mL) receiving calcitriol (2 microg after dialysis twice weekly). Clinical assessment, medication status, and biochemical and hematological measurements were performed once a month. Throughout the study, calcium carbonate levels were modified to maintain serum phosphate levels at less than 6 mg/dL, but body weight, antihypertensive medication, and ultrafiltration dose remained constant. In patients treated with calcitriol, an adequate reduction of iPTH levels was found (1,112 +/- 694 v 741 +/- 644 pg/mL; P < 0.05) without changes in values of serum ionized calcium (iCa++), phosphate, or hematocrit. Blood pressure (BP), cardiac output (CO), and total peripheral resistance (TPR) did not significantly change. After 15 weeks of treatment with calcitriol, M-mode echocardiograms showed pronounced reductions in interventricular wall thickness (13.9 +/- 3.6 v 12.8 +/- 3.10 mm; P = 0.01), left ventricular posterior wall thickness (12.5 +/- 2.4 v 11.3 +/- 1.8 mm; P < 0.05), and left ventricle mass index (LVMi; 178 +/- 73 v 155 +/- 61 g/m2; P < 0.01). However, in control patients, these changes were not found after the treatment period. In addition, sequential measurements of neurohormonal mediator levels in patients receiving calcitriol showed that plasma renin (18.5 +/- 12.7 v 12.3 +/- 11.0 pg/mL; P = 0.007), angiotensin II (AT II; 79.7 +/- 48.6 v 47.2 +/- 45.7 pg/mL; P = 0.001), and atrial natriuretic peptide (ANP; 16.6 +/- 9.7 v 12.2 +/- 4.4 pg/mL; P = 0.03) levels significantly decreased, whereas antidiuretic hormone (ADH), epinephrine, and norepinephrine levels did not change significantly. The percent change in LVMi associated with calcitriol therapy had a strong correlation with the percent change in iPTH (r = 0.52; P < 0.05) and AT II (r = 0.47; P < 0.05) levels. We conclude that the partial correction of SHPT with intravenous calcitriol causes a regression in myocardial hypertrophy without biochemical or hemodynamic changes, such as heart rate, BP, and TPR. The changes in plasma levels of iPTH and, secondarily, plasma levels of neurohormones (especially AT II) after calcitriol therapy may have a key role in attenuating ventricular hypertrophy in SHPT.

Alterations of Fas (Apo-1/CD95) gene in non-small cell lung cancer

Fas (Apo-1/CD95) is a cell-surface receptor involved in cell death signaling. The key role of the Fas system in negative growth regulation has been studied mostly within the immune system, and somatic mutations of Fas gene in cancer patients have been described solely in lymphoid-lineage malignancies. However, many non-lymphoid tumor cells have been found to be resistant to Fas-mediated apoptosis, which suggests that Fas mutations, one of the possible mechanisms for Fas-resistance, may be involved in the pathogenesis of non-lymphoid malignancies as well. In this study, we have analysed the entire coding region and all splice sites of the Fas gene for the detection of the gene mutations in 65 human non-small cell lung cancers by polymerase chain reaction, single strand conformation polymorphism and DNA sequencing. Overall, five tumors (7.7%) were found to have the Fas mutations, which were all missense mutations. Four of the five mutations identified were located in the cytoplasmic region (death domain) known to be involved in the transduction of an apoptotic signal and one mutation was located in the transmembrane domain. This is the first report on the Fas gene mutations in non-lymphoid malignancies, and the data presented here suggests that alterations of the Fas gene might lead to the loss of its apoptotic function and contribute to the pathogenesis of some human lung cancers.

Methoxy poly(ethylene glycol)/epsilon-caprolactone amphiphilic block copolymeric micelle containing indomethacin. I. Preparation and characterization

Amphiphilic diblock copolymers composed of methoxy polyethylene glycol (MePEG) and epsilon-caprolactone (epsilon-CL) were prepared for the formation of micelles. The copolymer was formed by ring opening mechanism of epsilon-CL in the presence of MePEG containing hydroxyl functional groups at one end of the chain. To estimate their feasibility as vehicles for drugs, MePEG/epsilon-CL block copolymeric micelles were prepared by dialysis against water. Indomethacin was incorporated into the hydrophobic inner core of these micelles as a typical model drug for non-steroidal anti-inflammatory drugs. From the dynamic light scattering measurements, the size of micelle formed was less than 200 mm, and their size increases with the amount of indomethacin encapsulated into the inner core of MePEG/epsilon-CL block copolymers. The selected solvents used to prepare micelles by dialysis in water affect the size of polymeric micelles. As the hydrophobic components of copolymer increase, the critical micelle concentration values and hydrophilic-lipophilic balance decreased. An increase of molecular weight and hydrophobic components of diblock copolymer produced larger micelles.

Assessing the competence of persons with Alzheimer's disease in providing informed consent for participation in research

OBJECTIVE

The capacity of persons with Alzheimer's disease or other neuropsychiatric disorders for giving consent to participate in research has come under increasing scrutiny. While instruments for measuring abilities related to capacity have been developed, how they should be used to categorize subjects as capable or incapable is not clear. A criterion validation study was carried out to help address this question.

METHOD

The authors measured the ability of 37 subjects with mild-to-moderate Alzheimer's disease and 15 elderly comparison subjects to provide consent for participation in a hypothetical clinical trial. Using the judgment of three experts as the criterion standard, the authors performed a receiver operator characteristic analysis for the capacity ability measures from the MacArthur Competence Assessment Tool-Clinical Research VERSION: The results were compared with categorizations of capacity status that were based on normative values.

RESULTS

While most comparison subjects scored perfectly on all measures of the competence assessment tool, the majority of the group with Alzheimer's disease showed significant decision-making impairment. Thresholds based on normative values resulted in 84% (N=31) of the Alzheimer's disease subjects being rated as incapable on at least one ability; thresholds based on expert judgment resulted in 62% (N=23) failing to meet cutoff scores on at least one ability.

CONCLUSIONS

Even relatively mild Alzheimer's disease significantly impairs consent-giving capacity. But differentiating capable from incapable subjects remains an issue despite the aid of standardized tools. More research is needed to understand the relationship between subject factors (performance on ability measures) and categorical judgments about their capacity.

alpha-Synuclein gene duplication is present in sporadic Parkinson disease

OBJECTIVE

alpha-Synuclein gene (SNCA) multiplication was found in familial Parkinson disease (PD). We examined SNCA multiplication in patients with familial and sporadic PD and multiple system atrophy (MSA).

METHODS

We screened 1,106 patients with parkinsonism (PD = 906, MSA = 200) for SNCA multiplication by multiplex PCR. Fluorescent in situ hybridization was done to confirm the multiplication. [(123)I]N-omega-Fluoropropyl-2 beta-carbomethoxy-3beta-(4-iodophenyl)-tropane ([(123)I]FP-CIT) SPECT was done in the patients with SNCA multiplication and their family members.

RESULTS

Three patients were identified as having SNCA duplication. One patient had a positive family history, and two patients were sporadic. Each patient had asymptomatic carriers in their families. The familial case had early onset parkinsonism with rapidly progressive course, cognitive impairment, and dysautonomia. Sporadic cases were more typical of PD. [(123)I]FP-CIT SPECT was abnormal in the patients and normal in the asymptomatic carriers.

CONCLUSION

SNCA multiplication is present in sporadic Parkinson disease (PD) and needs to be screened. Low penetrance, clinical heterogeneity, and normal dopamine transporter imaging in asymptomatic carriers may suggest the presence of other genetic modifiers or environmental triggers that play a role in the pathogenesis of PD due to SNCA duplication.

Differential expression of multiple transglutaminases in human brain. Increased expression and cross-linking by transglutaminases 1 and 2 in Alzheimer's disease

The transglutaminase (TGase) family of enzymes, of which seven different members are known in the human genome, participate in many biological processes involving cross-linking proteins into large macromolecular assemblies. The TGase 2 enzyme is known to be present in neuronal tissues and may play a role in neuronal degenerative diseases such as Alzheimer's disease (AD) by aberrantly cross-linking proteins. In this paper, we demonstrate by reverse transcriptase-polymerase chain reaction and immunological methods with specific antibodies that in fact three members, the TGase 1, TGase 2, and TGase 3 enzymes, and are differentially expressed in various regions of normal human brain tissues. Interestingly, the TGase 1 and 3 enzymes and their proteolytically processed forms are involved in terminal differentiation programs of epithelial cell development and barrier function. In addition, we found that the levels of expression and activity of the TGase 1 and 2 enzymes were both increased in the cortex and cerebellum of AD patients. Furthermore, whereas normal brain tissues contain approximately 1 residue of cross-link/10,000 residues, AD patient cortex and cerebellum tissues contain 30-50 residues of cross-link/10,000 residues. Together, these findings suggest that multiple TGase enzymes are involved in normal neuronal structure and function, but their elevated expression and cross-linking activity may also contribute to neuronal degenerative disease.

Extracellular vesicles, exosomes and shedding vesicles in regenerative medicine - a new paradigm for tissue repair

Tissue regeneration by stem cells is driven by the paracrine activity of shedding vesicles and exosomes, which deliver specific cargoes to the recipient cells. Proteins, RNA, cytokines and subsequent gene expression, orchestrate the regeneration process by improving the microenvironment to promote cell survival, controlling inflammation, repairing injury and enhancing the healing process. The action of microRNA is widely accepted as an essential driver of the regenerative process through its impact on multiple downstream biological pathways, and its ability to regulate the host immune response. Here, we present an overview of the recent potential uses of exosomes for regenerative medicine and tissue engineering. We also highlight the differences in composition between shedding vesicles and exosomes that depend on the various types of stem cells from which they are derived. The conditions that affect the production of exosomes in different cell types are deliberated. This review also presents the current status of candidate exosomal microRNAs for potential therapeutic use in regenerative medicine, and in applications involving widely studied organs and tissues such as heart, lung, cartilage and bone.

Isolation of a novel class of bZIP transcription factors that interact with ABA-responsive and embryo-specification elements in the Dc3 promoter using a modified yeast one-hybrid system

Dc3 is a carrot lea class gene that is abundantly expressed during somatic and zygotic embryogenesis. Its expression is normally embryo-specific and also can be induced by abscisic acid. The regulatory elements mediating the embryo-specific expression of Dc3 reside within the proximal promoter region (-117 to +26), which is also essential for ABA-induced expression. In this study, an optimized version of the yeast one-hybrid system has been used to clone factors that bind to the promoter region of the Dc3 gene. Twenty-five million yeast transformants were screened in a single experiment, and nine independent cDNA clones were isolated from a sunflower library that encode proteins that specifically bind to functional cis-regulatory elements in the Dc3 promoter. Analysis of these clones showed that they are derived from three different mRNA species that encode two basic leucine zipper proteins. The basic regions of these proteins, named DPBF-1 and 2 (Dc3 Promoter-Binding Factor-1 and 2), respectively, are nearly identical to each other and are similar to the plant G-box binding factor GBF-4. Outside the basic region, however, DPBF-1 and 2 diverge significantly from each other and from other known factors. Both factors have transcriptional activity in yeast, and bind to DNA as dimers. Unlike other plant bZIP factors, DPBF-1 and 2 recognize sequences containing the ACACNNG core. Cloning of these factors demonstrates the power of the one-hybrid approach when optimally applied.

Superoxide modulates the oxidation and nitrosation of thiols by nitric oxide-derived reactive intermediates. Chemical aspects involved in the balance between oxidative and nitrosative stress

Thiol-containing proteins are key to numerous cellular processes, and their functions can be modified by thiol nitrosation or oxidation. Nitrosation reactions are quenched by O-2, while the oxidation chemistry mediated by peroxynitrite is quenched by excess flux of either NO or O-2. A solution of glutathione (GSH), a model thiol-containing tripeptide, exclusively yielded S-nitrosoglutathione when exposed to the NO donor, Et2NN(O)NONa. However, when xanthine oxidase was added to the same mixture, the yield of S-nitrosoglutathione dramatically decreased as the activity of xanthine oxidase increased, such that there was a 95% reduction in nitrosation when the fluxes of NO and O-2 were nearly equivalent. The presence of superoxide dismutase reversed O-2-mediated inhibition, while catalase had no effect. Increasing the flux of O-2 yielded oxidized glutathione (GSSG), peaking when the flux of NO and O-2 were approximately equivalent. The results suggest that oxidation and nitrosation of thiols by superoxide and NO are determined by their relative fluxes and may have physiological significance.

Taxol-loaded block copolymer nanospheres composed of methoxy poly(ethylene glycol) and poly(epsilon-caprolactone) as novel anticancer drug carriers

We prepared the methoxy poly(ethylene glycol) (MePEG)/poly(epsilon-caprolactone) (PCL) amphiphilic block copolymeric nanospheres containing taxol which has promising anticancer activity. MePEG/PCL block copolymeric nanospheres (MEP50) showed a narrow size distribution and an average diameter of less than 100 nm. When the initial weight ratio of taxol to polymer was 0.5:1.0, we could obtain the nanospheres having a relatively high drug-loading of more than about 20%. The size of the MePEG/PCL nanospheres also increased according to the taxol loading. However, the nanospheres did not exhibit a significant change in the size distribution and also showed a size of less than 100 nm for even that with drug-loading content (DLC) of about 20%. From the 1H NMR analysis, we identified that the MePEG/PCL nanospheres prepared by dialysis procedure have core-shell structure consisting of the hydrophilic outer shell of MePEG and the hydrophobic inner core of PCL. We confirmed the low toxicity of MePEG/PCL nanospheres (MEP70) in the acute toxicity study using male ICR mice. In addition, considering the extremely lipophilic characteristics of taxol, this MePEG/PCL, nanosphere system with high taxol loading content and suspended properties in water could be useful for the delivery of taxol.

Convenient colorimetric and fluorometric assays for S-nitrosothiols

S-nitrosothiols have been shown to affect a number of physiological functions. Several techniques have been used to detect these species in biological systems, primarily by methods utilizing chemiluminescence. Since the apparatus required for measurement of chemiluminescence are not readily available in most laboratories, methods employing more conventional techniques such as uv-vis and fluorescence spectroscopy may be of greater use. Herein, we report the development of colorimetric and fluorometric methods for the reliable quantitation of S-nitrosothiols. Solutions containing sulfanilamide/N-(1-naphthyl)- ethylenediamine dihydrochloride or 2,2'-azinobis (3-ethylbenzthiazoline-6-sulfonic acid), when exposed to S-nitrosoglutathione (GSNO), S-nitrosocysteine, or S-nitrosoacteylpenicillamine, resulted in no absorbance changes in the range of 400-800 nm. Exposure to HgCl2 or Cu(acetate)2 resulted in release of nitric oxide (NO) from the S-nitrosothiols. The liberated NO reacted subsequently with oxygen and formed a chemical species which reacted with either analysis solution, resulting in an increase in absorption between 400 and 800 nm. A plot of RSNO versus absorbance was linear for both mercury(II) and copper(II) ions where the slope in the presence of mercury ion was significantly greater than that for copper ion. The sensitivity was as low as 5 microM RSNO using HgCl2. The fluorometric method using 2, 3-diaminonaphthalene as the scavenger of the NOsolidusO2 products gave a sensitivity of 50 nM for GSNO. In addition, S-nitrosylated proteins were quantitated using the fluorometric technique. These methods provide accurate determination of low concentrations of S-nitrosothiols, utilizing conventional spectroscopic techniques available in most laboratories.

Improved glycemic control without hypoglycemia in elderly diabetic patients using the ubiquitous healthcare service, a new medical information system

OBJECTIVE

To improve quality and efficiency of care for elderly patients with type 2 diabetes, we introduced elderly-friendly strategies to the clinical decision support system (CDSS)-based ubiquitous healthcare (u-healthcare) service, which is an individualized health management system using advanced medical information technology.

RESEARCH DESIGN AND METHODS

We conducted a 6-month randomized, controlled clinical trial involving 144 patients aged >60 years. Participants were randomly assigned to receive routine care (control, n = 48), to the self-monitored blood glucose (SMBG, n = 47) group, or to the u-healthcare group (n = 49). The primary end point was the proportion of patients achieving A1C <7% without hypoglycemia at 6 months. U-healthcare system refers to an individualized medical service in which medical instructions are given through the patient's mobile phone. Patients receive a glucometer with a public switched telephone network-connected cradle that automatically transfers test results to a hospital-based server. Once the data are transferred to the server, an automated system, the CDSS rule engine, generates and sends patient-specific messages by mobile phone.

RESULTS

After 6 months of follow-up, the mean A1C level was significantly decreased from 7.8 ± 1.3% to 7.4 ± 1.0% (P < 0.001) in the u-healthcare group and from 7.9 ± 1.0% to 7.7 ± 1.0% (P = 0.020) in the SMBG group, compared with 7.9 ± 0.8% to 7.8 ± 1.0% (P = 0.274) in the control group. The proportion of patients with A1C <7% without hypoglycemia was 30.6% in the u-healthcare group, 23.4% in the SMBG group (23.4%), and 14.0% in the control group (P < 0.05).

CONCLUSIONS

The CDSS-based u-healthcare service achieved better glycemic control with less hypoglycemia than SMBG and routine care and may provide effective and safe diabetes management in the elderly diabetic patients.

Stress increases brain-derived neurotropic factor messenger ribonucleic acid in the hypothalamus and pituitary

Brain-derived neurotropic factor (BDNF) is a member of the nerve growth factor family that is important for neuronal survival and plasticity. We recently demonstrated that stress decreases BDNF messenger RNA (mRNA) levels in the hippocampus, which raises the possibility that BDNF may play a role in regulation of the hypothalamic-pituitary-adrenal axis. The purpose of this study was to determine whether BDNF expression is present and influenced by stress in other brain areas relevant to control of the hypothalamic-pituitary-adrenal axis. Using in situ hybridization, we found that BDNF mRNA is present in the parvocellular portion of the hypothalamic paraventricular nucleus (PVN), the lateral hypothalamus, and the anterior and neurointermediate lobes of the pituitary in rats. Acute (2-h) or repeated immobilization stress increased BDNF mRNA in all of these areas. This was in distinct contrast to stress-induced decreases in extrahypothalamic areas, including the basolateral amygdala, claustrum, and cingulate cortex as well as the hippocampus. BDNF was expressed in both CRF and TRH neurons in the PVN. Reducing glucocorticoid or thyroid negative feedback increased BDNF mRNA in the PVN and anterior pituitary, but not in the neurointermediate lobe. These results suggest that BDNF is a stress-responsive intercellular messenger that may be an important component of the stress response.

Poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide)/poly(epsilon-caprolactone) (PCL) amphiphilic block copolymeric nanospheres. II. Thermo-responsive drug release behaviors

Amphiphilic block copolymers composed of relatively hydrophilic PEO-PPO-PEO block copolymer (Pluronic) and poly (epsilon-caprolactone) with hydrophobic character were synthesized by ring-opening polymerization of epsilon-caprolactone in the presence of PEO-PPO-PEO block copolymer using stannous octoate as a catalyst. Pluronic/PCL block copolymeric nanospheres with core-shell structure were prepared by dialysis method. They showed the average diameter of 116-196 nm depending on the type of copolymer. All the nanosphere samples exhibited a narrow size distribution. The critical micelle concentrations of Pluronic/PCL amphiphilic block copolymers determined by fluorescence spectroscopy were lower than that of the common low molecular weight surfactant. Their core-shell structure was confirmed by 1H NMR spectroscopy. Pluronic/PCL block copolymeric nanospheres exhibited the reversible change of size depending on the temperature. Release behaviors of indomethacin from Pluronic/PCL block copolymeric nanospheres also showed temperature dependence and a sustained release pattern. In addition, cytotoxicity test using an MTT assay method revealed that these indomethacin-loaded Pluronic/PCL nanospheres could remarkably reduce the cell damage compared with the unloaded free indomethacin.