The 40-kDa subunit of DNA fragmentation factor induces DNA fragmentation and chromatin condensation during apoptosis

We report here the reconstitution of a pathway that leads to the apoptotic changes in nuclei by using recombinant DNA fragmentation factor (DFF), a heterodimeric protein of 40 and 45 kDa. Coexpression of DFF40 and DFF45 is required to generate recombinant DFF, which becomes activated when DFF45 is cleaved by caspase-3. The cleaved fragments of DFF45 dissociate from the DFF40, the active component of DFF. Purified DFF40 exhibited an intrinsic DNase activity that was markedly stimulated by chromatin-associated proteins histone H1 and high mobility group proteins. DFF40 also triggered chromatin condensation when incubated with nuclei. These data suggest that DFF40 is sufficient to trigger both DNA fragmentation and chromatin condensation during apoptosis.

Preparation and blood compatibility of new silica-chitosan hybrid biomaterials

The development of new materials containing both organic and inorganic structures is of great interest with respect to achievement of obtaining the special properties, and the solgel process has provided new opportunities for making such materials. In this paper, new silica-chitosan hybrid biomaterials were produced by this technique, using biopolymer chitosan and its heparin-like derivative as the organic species to be incorporated into the silicon alkoxide (TEOS) based network. All the samples made were in form of thin, flexible films with optical clarity. Microphase separated structure was observed in the hybrid surface, with hydrophobic SiO2 and hydrophilic chitosan interleaved. These hybrid materials displayed good blood compatibility in comparison with their single component systems.

Transforming growth factor-beta, endothelin-1, and c-fos expression in necrotizing/crescentic IgA glomerulonephritis

BACKGROUND

Among our cases of IgA glomerulonephritis (IgAGN), 10% show necrotizing/extracapillary lesions involving a small percentage of glomeruli and associated with a certain degree of inflammation in absence of glomerular and interstitial scarring. In our experience, also in repeat biopsies, these cases of IgAGN have a worse prognosis probably because necrotizing/extracapillary lesions can repeat and accumulate, leading to the progression of damage. As it is well known that transforming growth factor-beta (TGF-beta) and endothelin-1 (ET-1) are key-factors in the progression of glomerulonephritis, aim of the study was to examine their expression in renal biopsies of primary IgAGN with necrotizing/crescentic lesions in complete absence of interstitial fibrosis. To obtain information about the mitogenic effect of ET-1, the expression of c-fos, whose upregulation by ET-1 has been established in culture, was also studied.

METHODS

Eighteen renal biopsies of patients with necrotizing/crescentic IgAGN were examined by immunohistochemistry with antibodies against TGF-beta, ET-1 and c-fos. The results were compared with those obtained on 22 cases of IgAGN characterized only by pure mesangial proliferation and 25 IgAGN biopsies with advanced, not active, glomerulointerstitial lesions.

RESULTS

In necrotizing/crescentic IgAGN glomerular TGF-beta appeared more positive than in cases characterized only by pure mesangial proliferation and was especially expressed on cellular crescents. In the interstitium, TGF-beta, ET-1 and c-fos were expressed by infiltrating leukocytes, tubules, and small vessels. This positivity, although similar as localization, was less diffuse than in biopsies with advanced interstitial damage, but significantly greater than in cases with pure mesangial proliferation.

CONCLUSIONS

Positivity of TGF-beta on cellular crescents is similar to that observed from other authors in different types of necrotizing/crescentic human glomerulonephritis and supports our hypothesis that this is a peculiar type of IgAGN. Moreover, interstitial expression of TGF-beta, ET-1 and c-fos in biopsies with glomerular active lesions but complete absence of interstitial fibrosis may potentially represent a signal of activation of mechanisms that induce and amplify the damage leading to further progression of the disease.

[Determination of Ondansetron in injection by high performance capillary zone electrophoresis]

Ondansetron is a kind of drug which is used for the treatment of nausea and vomiting induced by cytotoxic chemotherapy and radiotherapy. In this paper, a method to determine Ondansetron in injection by high performance capillary zone electrophoresis is discussed. The injection was directly introduced into the capillary employing 40 mmol/L phosphate at pH 4.03 as buffer. The capillary used was 75 microns in i.d. and 47 cm in length. UV detection was set at 254 nm. The calibration curve showed good linearity. The recovery of Ondansetron ranged from 95%-98% with a coefficient of variation of 1.05%(n = 4). This method is simple, rapid and reliable.

[Determination of HIgG in Human plasma by high performance membrane affinity chromatography(HPMAC)]

An assay technique for determination of Human IgG in human plasma has been developed by utilizing Protein A bound to the modified cellulose matrices based on the strong affinity between protein A and Fc region of IgG. The pH values of loading buffer and elution buffer were 7.0 and 2.3 respectively. The cartridge used was 20 mm x 4 mm i.d. and detection was carried out with a UV monitor at 280 nm. The non-specific adsorption of two kinds of media has been studied. The media without hexyldiamine arm gives very low non-specific adsorption BSA. The calibration curve showed a good linearity (correlation coefficient > 0.9992) in the injected amount range of 9-70 micrograms for HIgG. The total time for separation and determination was within 5 min and the total time of rapid assay was within 30 s. Relative standard deviations of peak areas were 1.5% (n = 5) and 3.6% (n = 3) for HIgG in standard solution and human plasma respectively.

Expression of a constitutively active type I BMP receptor using a retroviral vector promotes the development of adrenergic cells in neural crest cultures

Previous work has demonstrated that the bone morphogenetic proteins (BMP)-2, BMP-4, and BMP-7 can promote the development of tyrosine hydroxylase (TH)-positive and catecholamine-positive cells in quail trunk neural crest cultures. In the present work, we showed that mRNA for the type I bone morphogenetic protein receptor IA (BMPR-IA) was present in neural crest cells grown in the absence or presence of BMP-4. We have used a replication-competent avian retrovirus to express a constitutively active form of BMPR-IA in neural crest cells in culture. Cultures grown in the absence of BMP-4 and infected with retrovirus containing a construct encoding this activated BMPR-IA developed five times more TH-immunoreactive and catecholamine-positive cells than uninfected control cultures or cultures infected with virus bearing the wild-type BMPR-IA cDNA. The number of TH-positive cells which developed was dependent on the concentration of virus bearing the activated receptor cDNA used in the experiments. Most TH-positive cells which developed also contained viral p19 protein. Total cell number was not affected by infection with the virus containing the activated receptor construct. The effect of the activated receptor was phenotype-specific since infection with the virus bearing the activated receptor cDNA did not alter the number or morphology of microtubule-associated protein (MAP)2-immunoreactive cells, which are distinct from the TH-positive cell population. These findings are consistent with the observation that MAP2-positive cells are not affected by the presence of BMP-4. Taken together, these results suggest that activity of BMPR-IA is an important element in promoting the development of the adrenergic phenotype in neural crest cultures.

[Retention behaviours of neutral solutes in reversed-phase capillary electrochromatography]

In this paper, retention behaviours of neutral solutes in reversed-phase capillary electrochromatography (RP-CEC) was studied separately with methanol, acetonitrile, isopropanol and tetrahydrofuran as organic modifiers. It was found that at certain concentration, the order of mu eo was in accordance with the epsilon/eta value of the organic modifier in the mobile phase. In addition, the relationship between mu eo and phi was relevant to the property of the organic modifier. With more organic modifier in the mobile phase, mu eo increased in methanol-water and acetonitrile-water systems; it changed little in tetrahydrofuran-water system and decreased slightly in isopropanol-water system. Linear relationship between capacity factors of neutral solutes and the volume fraction of the organic modifier in the mobile phase was obtained in CEC, and was similar to that in RP-HPLC. With the same column under the same conditions, it was found that the capacity factors of solutes in RP-CEC and RP-HPLC were almost the same, which means that the retention mechanisms of neutral solutes in these two modes might be quite similar.

[Experimental study on the biocompatibility and toxicology of interface between hydroxyapatite coating and bone]

According to "The standards for biological evaluation of bio-materials and bio-products abbreviated to STANDARDS" newly set by the Ministry of Health, PRC, 5 observation indexes were selected to evaluate systematically the biocompatibility and toxicology of China-made hydroxyapatite, which is clinicall used. The results revealed no effects of allergy, mutation and hemoclasis reaction except mild cytotoxicity. These indicate that the China-made hydroxyapatite meets the demand of STANDADS and thus may be clinically with safety.

Quantitative study of competitive binding of drugs to protein by microdialysis/high-performance liquid chromatography

A displacement equation describing competitive binding of drugs to protein in solution is derived and examined with four nonsteroidal anti-inflammatory drugs and human serum albumin as model drugs and protein, respectively. Microdialysis/high-performance liquid chromatography was adopted to determine simultaneously the unbound solute and displacing agent in drug-protein solutions. The method is able to locate the binding site and determine affinity constants even up to 10(7) L/mol accurately. A comparison of association constants determined by this method and from capacity factors on HSA-CSP is given.

Stepwise gradient elution of capillary electrochromatography in the analysis of environmental samples

Two modes of stepwise gradient elution of capillary electrochromatography were developed for the analysis of environmental samples on both a laboratory-made and a commercial CE instrument. Using the laboratory-made apparatus, another mobile phase was dropped directly into the inlet vial with a pipet. By this means, nine 2,4-dinitrophenylhydrazine (DNPH)-derivatized ketones and aldehydes were separated with high resolution. Not only was analysis time shortened by more than one half, but the detection limit was greatly improved compared to that in isocratic elution. The latter was achieved using the P/ACE 5510 system (Beckman Instruments, Fullerton, CA, U.S.A.), which moved the mobile phase vials automatically. The stop-flow technique was utilized during transfer. It had no effect on solute retention. With this method, the concentration and type of organic modifier in the mobile phase could be changed. A mixture of 13 aromatic hydrocarbons was separated completely in 14 min by changing the mobile phase from 80% methanol to 80% acetonitrile and 90% acetonitrile in a sequential step mode. The RSD of the retention time of each component in six consecutive injections was below 0.374%. All of these results demonstrate that stepwise gradient elution of capillary electrochromatography may be useful in the analysis of complex environmental samples.

Multi-site binding of fenoprofen to human serum albumin studied by a combined technique of microdialysis with high performance liquid chromatography

A simple and fast method for the determination of the multi-site binding of fenoprofen (FP) to human serum albumin (HSA) has been developed by utilizing microdialysis sampling techniques combined with high performance liquid chromatography (HPLC). The drug and protein were mixed in different molar ratios in 0.067 Mol potassium phosphate buffer, pH 7.4, and incubated at 37 degrees C in a water-bath. Then the microdialysis probe was put in the FP-HSA solution and sampled at the perfusion rate of 1 microL/min. The concentrations of FP in microdialysates were determined by the reversed-phase high performance liquid chromatography. Relative recovery (R) was also determined in vitro on similar condition, R is about 56.03 +/- 1.11% (n = 3). Fenoprofen was found to bind to two classes of sites, the association constant (K1) and the number of the binding sites on primary binding sites of a HSA molecule (n1) for fenoprofen are 3.4 x 10(5)/M and 2.5, respectively, and those for secondary binding are 1.0 x 10(4)/M and 10.0, respectively. The competitive interaction of ibuprofen (IP) and palmitic acid with fenoprofen to HSA were also studied, both compounds significantly decrease the binding degree of fenoprofen to HSA.

[Determination of aniline derivatives in waste water with reversed-phase high performance liquid chromatography]

A reversed-phase high performance liquid chromatographic method for the determination of aniline derivatives in waste-water is described. Chromatographic conditions were: column, Hypersil BDS (200 mm x 4.0 mm i.d., 5 microm); mobile phase, methanol-water, gradient elution; flow rate, 1.0 mL/min; detection wavelength, 254 nm. Quantification was carried out based on the external standard of aniline derivatives. The pH of waste water sample was adjusted to 11-12 with dilute NaOH solution prior to extraction with CH2Cl2. The extractives concentrated in K-D concentrator and filtered with FH 0.5 microm membrane. Finally make up the volume to 1 mL and test it with reversed-phase high performance liquid chromatography. The linearity range of calibration curve used was 0.005-0.3 microg. The minimum detectable quantities of aniline derivatives varied from 1.20 ng to 3.00 ng. The average recoveries were from 51.57% to 107.92%, and the RSDs of the method were from 1.88% to 5.98%. The method is simple, rapid, and accurate.

Studies on the precursors of strong mutagen [3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone]MX by chlorination of fractions from different waters

The strong mutagen, [3-chloro-4-(dichloromethyl)-5-hydroxy- 2(5H)-furanone] MX, was found to be one of the most potent mutagens in drinking water. In this study, dissolved organic matters from river water and lake water were separated into several compound classes by sorbtion on a series of resin absorbents. After chlorine treatment of the fractions, MX was determined with GC/MS in the selected ion monitoring mode. Humic substances produced more MX on a TOC-basis than other fractions and contributed more to MX formation in the chlorinated natural waters. Some phenols were detected in the oxidation products of humic substances and therefore formation of MX may occur when some phenolic precursor structures in humic substances are treated with chlorine.

Apaf-1, a human protein homologous to C. elegans CED-4, participates in cytochrome c-dependent activation of caspase-3

We report here the purification and cDNA cloning of Apaf-1, a novel 130 kd protein from HeLa cell cytosol that participates in the cytochrome c-dependent activation of caspase-3. The NH2-terminal 85 amino acids of Apaf-1 show 21% identity and 53% similarity to the NH2-terminal prodomain of the Caenorhabditis elegans caspase, CED-3. This is followed by 320 amino acids that show 22% identity and 48% similarity to CED-4, a protein that is believed to initiate apoptosis in C. elegans. The COOH-terminal region of Apaf-1 comprises multiple WD repeats, which are proposed to mediate protein-protein interactions. Cytochrome c binds to Apaf-1, an event that may trigger the activation of caspase-3, leading to apoptosis.

[Theory of column performance and application of capillary electrochromatography]

56 papers are reviewed in this article showing the development of the column preparing techniques and the advances of the application of capillary electrochromatography (CEC).

Distinct roles of type I bone morphogenetic protein receptors in the formation and differentiation of cartilage

The bone morphogenetic proteins (BMPs), TGF beta superfamily members, play diverse roles in embryogenesis, but how the BMPs exert their action is unclear and how different BMP receptors (BMPRs) contribute to this process is not known. Here we demonstrate that the two type I BMPRs, BMPR-IA and BMPR-IB, regulate distinct processes during chick limb development. BmpR-IB expression in the embryonic limb prefigures the future cartilage primordium, and its activity is necessary for the initial steps of chondrogenesis. During later chondrogenesis, BmpR-IA is specifically expressed in prehypertrophic chondrocytes. BMPR-IA regulates chondrocyte differentiation, serving as a downstream mediator of Indian Hedgehog (IHH) function in both a local signaling loop and a longer-range relay system to PTHrP. BMPR-IB also regulates apoptosis: Expression of activated BMPR-IB results in increased cell death, and we showed previously that dominant-negative BMPR-IB inhibits apoptosis. Our studies indicate that in TGF beta signaling systems, different type I receptor isoforms are dedicated to specific functions during embryogenesis.

Apaf-1, a human protein homologous to C. elegans CED-4, participates in cytochrome c-dependent activation of caspase-3

We report here the purification and cDNA cloning of Apaf-1, a novel 130 kd protein from HeLa cell cytosol that participates in the cytochrome c-dependent activation of caspase-3. The NH2-terminal 85 amino acids of Apaf-1 show 21% identity and 53% similarity to the NH2-terminal prodomain of the Caenorhabditis elegans caspase, CED-3. This is followed by 320 amino acids that show 22% identity and 48% similarity to CED-4, a protein that is believed to initiate apoptosis in C. elegans. The COOH-terminal region of Apaf-1 comprises multiple WD repeats, which are proposed to mediate protein-protein interactions. Cytochrome c binds to Apaf-1, an event that may trigger the activation of caspase-3, leading to apoptosis.

Holliday junctions accumulate in replication mutants via a RecA homolog-independent mechanism

The Holliday junction recombination intermediate, an X-shaped DNA molecule (xDNA), was analyzed at rDNA in mitotically growing yeast. In wild-type cells, xDNA is only detected at S phase, suggesting that recombination is stimulated to repair replication-related lesions. A search for mutations that increase the level of xDNA uncovered a gene encoding a subunit of DNA polymerase alpha. Systematic examination of replication mutants revealed that defects in polymerase alpha and delta but not the epsilon complex stimulate the level of xDNA. These xDNAs are Holliday junctions and not replication intermediates. The level of Holliday junctions is greatly reduced in rad52 mutants, but surprisingly, not in mutants defective in the three known mitotically expressed yeast RecA homologs.

Glutathione S-transferase expression in hepatitis B virus-associated human hepatocellular carcinogenesis

Hepatitis B virus (HBV) and aflatoxin B1 represent the main risk factors for the development of hepatocellular carcinoma (HCC) in areas endemic for liver cancer. The glutathione S-transferases (GSTs) are a family of Phase II detoxification enzymes that catalyze the conjugation of a wide variety of endogenous and exogenous toxins, including aflatoxin B1, with glutathione. This study characterizes the GST isoenzyme composition (alpha, mu, and pi) of both HBV-infected normal hepatic tissues and HCCs. Analysis of matched pairs of hepatic tissue (normal and tumor) from 32 HCC patients indicated that total GST activity was significantly higher in normal tissues than in tumor tissues, although the percentage of samples expressing GST alpha and pi was equivalent. GST mu was detected by Western blot in the normal tissue from 87.5% of the subjects possessing the GST M1 gene but only 28.6% of the corresponding tumor tissues. The GST activity of normal tissue from GST M1 null patients was significantly decreased as compared to that of subjects possessing the GST M1 gene (264.6 and 422.2 nmol/min/mg, respectively; P = 0.005). GST pi appeared to be overexpressed in the normal tissue of GST M1 null patients, a potential compensatory effect. Patients positive for HBV DNA had significantly lower GST activity than those who were HBV negative (302.1 versus 450.0 nmol/min/mg, respectively; P = 0.02). These results suggest that cellular protection within the human liver is compromised by HBV infection and further decreased during hepatocellular tumorigenesis.

Correlation of the intercept and slope of the retention equation ln k' = ln k'w - SC in MECC with the solvatochromic parameters of solutes

The intercept (ln k'w) and slope (S) of the retention equation in k' = ln k'w - SC in micellar electrokinetic capillary chromatography (MECC) have been studied through linear solvation energy relationships (LSER). It has been observed that the ln k'w is dependent on the properties of micelle and solute but independent of the properties of organic modifier, while the slope (S) is related to the organic modifier and the solute. The LSER results show that the ln k'w of solute is primarily determined by its molecular size and hydrogen bond acceptor (HBA) basicity, whereas the S of solute is primarily determined by its properties in terms of the type of organic modifier, of which molecular size is the most important factor. Additionally, the LSER results show that the interactions of micelle-water and water-organic modifier are also important factors for the retention of solute.

Immobilized IDA-type Cu2+-chelating membrane affinity chromatography for purification of bovine liver catalase

Cu2+-chelating membrane medium based on iminodiacetate-substituted modified short cotton cellulose was examined to purify bovine liver catalase (BLC) by affinity chromatography. The buffer pH notably affect BLC binding to the Cu2+-chelating membrane adsorbent. The results showed that under the chromatographic conditions chosen, 67.7% recovery of BLC attained with an overall 4.7-fold increase in specific activity in a single step. After purification of BLC, the chelating membrane adsorbent can easily be regenerated by imidazole or EDTA buffer. Different results were obtained by the two regeneration methods: the later is more effective than the former in reviving the purification characters of the chelating membrane adsorbent.

[Research on the reproducibility and selection of experimental conditions of capillary electrochromatography]

In this work, we prepared the packed columns for capillary electrochromatography (CEC) with 75microm and 100microm i.d., both of coupled mode and uncoupled mode. A mixture of thiourea and other three aromatic compounds was employed to evaluate the efficiency of the CEC columns. RSD values of retention times smaller than 2.12% was obtained on the home-made CEC system. The influence of pH value and the concentration of the organic solvent in the buffer on the retention behavior was investigated, giving a guide to the selection of experimental conditions. High speed analysis can be achieved by using high pH value buffers. Higher concentration of acetonitrile will improve the elution ability, while lower ocncentration of acetonitrile would improve the resolution. Seven kinds of neutral molecules were separated efficiently within 25 minutes. The results from the two modes of CEC columns were compared.

[Research on the variation of peak shape in capillary zone electrophoresis]

The influence of operation conditions, such as, injection time, applied voltage and effective length of capillary column, on parameters of peak shape in capillary zone electrophoresis (CZE) was investigated by using exponential-modified Gaussian (EMG) equation. The CE experiments were carried out by using the sample of derivatives of benzoic acid and small peptides. The experimens indicated that there was a significant effect of injection time on W1/2 and that the peaks changed from tailing to leading when the injection time was over 3 seconds in the case of pressure injection. It is recommended that an injection time less than 3 seconds can lead to a good column efficiency. The good linear relationships between tm and tau, sigma, W1/2 (t) with different separation voltages were observed. In the range of experimental conditions (11-27kV), higher voltage could lead to smaller zone dispersion, giving rapid and high efficient separation, and the voltage was insignificant on peak tailing. It was also shown that sigma, tau and W1/2 increased slightly with increasing the effective length of capillary column.