Phenotyping of esterase D and acid phosphatase by rapid isoelectric focusing on PhastSystem

A rapid isoelectric focusing method on PhastSystem was applied to investigate the distribution of esterase D (ESD) and acid phosphatase (ACP) phenotypes in 152 and 112 unrelated healthy donors, respectively, from the Han population in Beijing. Laboratory-made gels with a pH range of 5.0-7.0 and 5.0-8.0 were used for analysis of ESD and ACP, respectively, with 1 microliter sample loading. The running time was 30-40 min. Gene frequencies for ESD were 0.6809 for ESD*1 and 0.3191 for ESD*2, (sigma chi 2 = 0.8586 and P > or = 0.50); gene frequencies of ACP were 0.2009 for ACP*A, 0.7991 for ACP*B, (sigma chi 2 = 1.7892 and P > 0.20), with good agreement between the observed and the expected values.

Direct injection of large volumes of plasma in a column-switching system for the analysis of local anaesthetics. I. Optimization of semi-permeable surface precolumns in the system and characterization of some interference peaks

Possibilities for accomplishing direct injection of large volumes (500 microliters) of plasma samples into a column-switching HPLC system were investigated. A new format of precolumn containing a semi-permeable surface (SPS) support (1 cm x 1 cm) was used for the sample clean-up and trace enrichment and was combined with a Kromasil C18 column for the final separation. A stable chromatographic system with respect to the separation selectivity and separation time was constructed and evaluated. The main parameters were the hydrophobicity of the SPS column, pH of the eluents, concentration of the organic modifier in the eluents and the detection wavelength. Two main interference peaks that were eluted in front of the ropivacaine peak were systematically characterized by varying the loading conditions for the SPS precolumn. The SPS column could tolerate large volumes (< or = 500 microliters) of plasma injections with a total volume of more than 50 ml. The developed system is stable, which permits the detection of 30 ng/ml ropivacaine in human plasma.

Direct injection of large volumes of plasma in a column-switching system for the analysis of local anaesthetics. II. Determination of bupivacaine in human plasma with an alkyldiol silica precolumn

A column-switching high-performance liquid chromatographic system was applied for the determination of bupivacaine in plasma. A 500-microliter plasma sample was directly introduced onto a C18-alkyl-diol silica (ADS) precolumn separating analytes from proteins and polar endogenous compounds. The fraction containing bupivacaine and ropivacaine (internal standard) was back-flushed and transferred to a conventional reversed-phase column (Kromasil C18) for final separation. A single ADS precolumn could withstand more than 50 ml of plasma injections without changing analytical performance. Quantitative studies showed a broad range of linearity (0.033-3.31 micrograms/ml) and high recovery (95-99.9%) with coefficients of variation less than 3.1%. The advantages of the ADS material are its high capability of sample clean-up, due to rapid elution of plasma proteins and endogenous compounds to waste, and its ability to elicit a stable baseline. As a result, UV detection could be performed at 210 nm and clean chromatograms with baseline separation for desired peaks were obtained within 15 min. The detection limit of this system was 10 ng/ml defined by a signal-to-noise ratio of 3:1. The concentration of bupivacaine in patients determined by this method agreed well with the values obtained from an alternative method, making the technique applicable for pharmacokinetic studies in humans.

[A pilot study on trihalomethane formation in water treated by chlorine dioxide]

Trihalomethane (THM) formation was determined by gas chromatography in water disinfected with chlorine dioxide (ClO2) only or ClO2 combined with chlorine (Cl2), to lay a basis for water disinfected with ClO2. Results showed no THM was produced in water disinfected with ClO2 only if without existence of bromine (Br) ion in it; certain amount of bromoform could be formed with existence of bromine ion, and THM formation could be inhibited by ClO2 and Cl2, with a ratio of greater than 1 between them. Light irradiation could decrease the amount of THM produced whether in disinfection with ClO2 or combination with ClO2 and Cl2. No significant effect of pH value of water on THM formation was observed, but pH should be controlled under neutral or slightly acidic to ensure the concentration of ClO2 in water.

Mch3, a novel human apoptotic cysteine protease highly related to CPP32

Recent evidence suggests that mammalian cysteine proteases related to Caenorhabditis elegans CED-3 are key components of mammalian programmed cell death or apoptosis. We have shown recently that the CPP32 and Mch2 alpha cysteine proteases cleave the apoptotic markers poly(ADP-ribose) polymerase (PARP) and lamins, respectively. Here we report the cloning of a new Ced-3/interleukin 1 beta-converting enzyme-related gene, designated Mch3, that encodes a protein with the highest degree of homology to CPP32 compared to other family members. An alternatively spliced isoform, named Mch3 beta, was also identified. Bacterially expressed recombinant Mch3 has intrinsic autocatalytic/autoactivation activity. The specific activity of Mch3 alpha toward the peptide substrate DEVD-7-amino-4-methylcoumarin and PARP resembles that of CPP32. Like interleukin 1 beta-converting enzyme and CPP32, the active Mch3 alpha is made of two subunits derived from a precursor (proMch3 alpha). It was of interest that recombinant CPP32-p17 subunit can form an active heteromeric enzyme complex with recombinant Mch3 alpha-p12 subunit and vice versa, as determined by the ability of the heteromeric complexes to induce apoptosis in Sf9 cells. These data suggest that proMch3 alpha and proCPP32 can interact to form an active Mch3 alpha/CPP32 heteromeric complex. We also provide evidence that CPP32 can efficiently cleave proMch3 alpha, but not the opposite, suggesting that Mch3 alpha activation in vivo may depend in part on CPP32 activity. The high degree of conservation in structure and specific activity and the coexistence of Mch3 alpha and CPP32 in the same cell suggests that the PARP cleavage activity observed during apoptosis cannot solely be attributed to CPP32 but could also be an activity of Mch3 alpha.

Effect of dynamic loading methods on cement film thickness in vitro

PURPOSE

Reduced cement flm thicknesses can improve crown seating and decrease marginal discrepancies. Improved marginal adaptation has the potential to reduce plaque accumulation, periodontal disease, and cement dissolution. Studies have indicated that dynamic seating methods can reduce seating discrepancies associated with zinc phosphate and resin cements. However, other types of cements and other dynamic techniques have not yet been studied or compared, nor has the mechanism for improved seating been fully explained. Therefore, the purpose of this study was to investigate the effect of a variety of loading methods on the film thicknesses of current types of crown and fixed partial denture cements compressed between glass plates.

MATERIALS AND METHODS

This study investigated the effect of three dynamic loading methods on film thickness of six representative fixed prosthodontic cements. These included zinc phosphate, resin-modified glass ionomer, encapsulated glass ionomer, adhesive composite resin, composite resin, and polycarboxylate. The method was derived from American Dental Association specifications for cement film thickness. In control groups, the cements were placed between two glass glass plates and statically loaded with a 15-kg weight. The test groups were initially similarly loaded, and then for 30 seconds further subjected to simulated repeated patient opening and closing, vibrations from an electromallet, or an ultrasonic device.

RESULTS

Mean film thicknesses ranged from 7.4 micrometers for polycarboxylate / ultrasound up to 40.3 micrometers for composite resin / static. Two-way analysis of variance revealed that the effects of material type and cementation method and their interaction all significantly affected film thickness (P < .0001). Multiple range analysis showed that dynamic methods were generally superior to static loading and that the ultrasonic method was the best overall.

CONCLUSIONS

The different dynamic loading methods all significantly decreased cement film thicknesses between glass plates. The ultrasonic method was the most effective. The type of cement used also influenced film thickness. Composite resins were more affected than other materials.

Characterization of a Human Stromal Cell Line Supporting Hematopoietic Progenitor Cell Proliferation: Effect of HIV Expression

Our objective was to determine the role that bone marrow-derived stromal cells have on human hematopoiesis in HIV infection. In particular, we dissected the heterogeneous bone marrow microenvironment to study the effect HIV expression might have on the cell population capable of producing the cytokines which will support human CD34+ cell differentiation. A stromal cell line, Lof(11-10), was established from human bone marrow by transfecting a plasmid containing the SV40 large T-antigen and isolating foci exhibiting a transformed phenotype. The Lof(11-10) cell line was characterized to determine its susceptibility to HIV infection, to identify its cytokine production profile, and to test the ability of conditioned media from this line to support CD34+ cell differentiation in the presence and absence of HIV expression. Nine cytokines were detected by RT-PCR and ELISA analysis. Conditioned media obtained from the Lof(11-10) cell line was able to support CD34+ celle differentiation. However, because the Lof(11-10) cells are not infectible by HIV, molecular clones of HIV were introduced into these cells by transfection. There was no qualitative difference in the levels of cytokine production between HIV-expressing and control Lof(11-10) cells. Furthermore, conditioned media derived from HIV-expressing and control Lof(11-10) cells added to bone marrow-derived CD34+ progenitor cells yielded similar colony formation in methylcellulose assays. Our data suggest that HIV infection of the cytokine-producing cells within the bone marrow microenvironment, as represented by the Lof(11-10) cell line, results in both normal cytokine production and hematopoiesis in spite of HIV expression. This report adds to the evidence against stromal cells being a significant target of HIV and establishes a system for comparison with more relevant models. Copyright 1995 S. Karger AG, Basel

[Relative changes between calcium content and number of atrial specific granules induced by water and salt loading]

Rats prepared by either deprivation of water intake for 5 d or drinking 2% NaCl solution for 4 d were sacrificed for dissection of auricle, and making ultrathin sections. The numerical density (Nv) of atrial specific granules (ASG) were counted by using electron microscopic morphometry, and Ca concentration in ASG and in terminal cisterna of sarcoplasmic reticulum (TSR) was determined by using electron microscopic X-ray microanalysis. In the drinking 2% NaCl solution group, the Nv of ASG decreased from 6.02 +/- 2.30 to 2.96 +/- 1.62/microns 3 (P < 0.01) and all companied by a decrease of Ca concentration from 64 +/- 16 to 38 +/- 21 mmol/kg (P < 0.01), while the secretion of atrial natriuretic peptide (ANP) showed some increase. Water deprivation induced all the contrary results. However, the Ca concentration in TSR was not affected by water-salt loading. It is suggested that when the atrial cardiocytes were stimulated by salt loading, Ca in ASG was released into cytosol and thus promoted fusion of ASG membrane with sarcolemma which resulted in release of ANP. Therefore, it is considered that ASG as an intracellular Ca store participates in the stimulus-secretion coupling of ANP through the release of Ca ions.

Sex chromosome complement and developmental diversity in pre-and post-hatching porcine embryos

To examine sex and development relationships in porcine embryos in early gestation, 10 gilts were killed on Day 4, 5, or 6 post mating (first day of standing estrus = Day 0). Embryos recovered immediately after slaughter were cultured in Medium 199 with colcemid (0.05mug/ml), fixed on slides, and stained with 4% Giemsa. The number of cells in each specimen was counted from the slides, and, whenever cell dispersion allowed, sex was determined by presence or absence of the Y-chromosome in at least 2 spreads from each embryo. Three gilts slaughtered on Day 4 yielded 2- and 4-cell stage embryos (n = 38), but no data on sex could be obtained due to lack of mitosis or readable metaphase spreads. Three Day 5 litters had individual specimens ranging from 8 to 14 cells (n = 8), 32 to 64 cells (n = 10), and 13 to 31 cells (n = 11), with the sex determined in 15 of these. Cell numbers ranged from 18 to 165 (n = 14), 16 to 32 (n = 9), 36 to 82 (n = 12), and 16 to 30 (n = 9) in the 4 gilts slaughtered on Day 6, with the sex determined in 26 of these. Embryos within each litter were divided into low, medium and high cell numbers by 3 equal divisions of the range of cell numbers. Three Day-5 embryos and 1 Day-6 embryo were lost during preparation; neither the cell numbers nor the sex could be determined in 4 Day-5 and in 3 Day-6 embryos. The overall sex ratio approximated 1:1, but on Day 5, the ratios for males to females were 0:5, 1:3 and 6:0 for the low, medium and high cell number groups, respectively. Embryos of undetermined sex in these same groups numbered 3, 1 and 3, respectively. On Day 6 the distribution was 1:11, 4:2 and 8:0 in favor of the males, while embryos of undetermined sex in the low, medium and high cell number groups numbered 5, 7 and 2, respectively. Chi-square analysis of the combined Day-5 and Day-6 results indicated the presence of significantly more females among embryos with low cell numbers and more males in the high cell number group (P < 0.01).

Adhesion of denture tooth porcelain to heat-polymerized denture resin

Use of porcelain denture teeth may be desirable in many clinical situations, including implant-supported prostheses. However, lack of space because of frameworks often precludes the use of conventional retention by diatorics and pins. Adhesion of porcelain denture teeth to denture resin could also stiffen and possibly strengthen dentures and decrease stain ingress between porcelain teeth and resin denture bases. Unlike previous studies that investigated the bond between conventional feldspathic metal-ceramic porcelain and bis-GMA based composite resin, this study investigated adhesion of denture tooth porcelain to polymethyl methacrylate (PMMA). High-energy air abrasion, hydrofluoric acid etching, and the use of a general purpose bonding agent resulted in an improved bond strength of heat-cured denture PMMA bonded to denture tooth porcelain. Silane coating did not improve bond strengths, and conventional air abrasion was no more effective than polishing with 600-grit silicon carbide. Storage in water and artificial aging substantially decreased bond strengths. The strongest bond strengths were achieved by a high-energy-abrasion + etching + multi-purpose bonding-agent treatment, but a simpler etching + multiple-purpose bonding-agent treatment also produced reliable results. A laboratory technique was suggested. The role of surface treatment in the mechanism of adhesion was examined with scanning electron microscopy. High-energy abrasion produced a slightly more detailed initial topography than conventional air abrasion, but after etching, the high-energy topography became much more detailed. Surface topography alone did not account for all differences found.

Influence of hemodialysis membranes on gene expression and plasma levels of interleukin-1 beta

Plasma levels of interleukin-1 beta (IL-1 beta) were measured in 10 normal subjects, in 11 nondialyzed end-stage renal failure (ESRD) patients, and in 22 hemodialysis (HD) patients. Of the HD patients, 7 were dialyzed with Cuprophan (CU), 7 with polymethylmethacrylate (PMMA), and 8 with polysulphone (PS) dialyzers. In normal controls, nondialyzed ESRD patients, and HD equipped with CU, PAMM, and PS dialyzers, plasma levels of IL-1 beta were 10.73 +/- 5.24 pg/ml, 9.97 +/- 3.61 pg/ml, 13.17 +/- 4.04 pg/ml, 15.16 +/- 6.16 pg/ml, and 13.96 +/- 5.47 pg/ml, respectively. There were no statistically significant differences among the groups (p > or = 0.05). In contrast, the gene expression of IL-1 beta for peripheral blood mononuclear cells (PBMC) by in situ hybridization showed differences among the groups. The gene for IL-1 beta for PBMC appears in HD equipped with different membranes, but not in cases of nondialyzed uremic patients and normal subjects. With computer imaging analysis, we carried out quantitative analysis of cells in in situ hybridization with an area of positive spots to an area of total cells. In HD with CU, PMMA, and PS, the results were 10.64 +/- 1.07, 3.34 +/- 0.74, and 3.27 +/- 0.64%, respectively. The levels of IL-1 beta gene expression in CU were higher than that in PMMA or PS. There were statistically significant differences (p < or = 0.001) between CU and PMMA or PS and no significant difference between the PMMA and PS (p > or = 0.05). We suggest measuring the gene expression of cytokines for PBMC and which may be better than measuring cytokine levels only for investigating the blood compatibility of dialyzers, which may help in understanding chronic complications of the dialysis procedure.

Genetic immunization against herpes simplex virus. Protection is mediated by CD4+ T lymphocytes

Plasmid DNA encoding proteins represent a convenient novel approach to vaccination. We have investigated this "genetic immunization" approach as a means to protect against herpes simplex virus (HSV) infection using a mouse zosteriform model that mimics several aspects of reactivated HSV infection of humans. After i.m. immunization with plasmid DNA-encoding glycoprotein B (gB), (pc-gB), 80% of BALB/c mice were completely protected and lesions were delayed in the remaining animals. Upon pc-gB vaccination, the animals developed both gB- and HSV-specific IgG Ab response and the isotype examination revealed a predominance of IgG2a. These mice also have low levels (1/16) of HSV-neutralizing Abs. Immune splenocytes obtained from pc-gB-immunized mice, when restimulated in vitro with HSV resulted in production of type 1 cytokines. Evidence for CD(8+)-mediated cytotoxic T lymphocyte response was equivocal. Protection could be adoptively transferred to nude mice recipients by CD4+ T cells from pc-gB-immunized mice but not by CD8+ T cells. Our results demonstrate that genetic immunization is a potent means of inducing protection against HSV and that the mechanism of immunity responsible for clearing virus from cutaneous sites is principally by CD4+ T cells. It is likely that these cells are Th1 cells because type 1 cytokines were the major cytokines detected upon in vitro Ag stimulation.

Genetic immunization against herpes simplex virus. Protection is mediated by CD4+ T lymphocytes

Plasmid DNA encoding proteins represent a convenient novel approach to vaccination. We have investigated this "genetic immunization" approach as a means to protect against herpes simplex virus (HSV) infection using a mouse zosteriform model that mimics several aspects of reactivated HSV infection of humans. After i.m. immunization with plasmid DNA-encoding glycoprotein B (gB), (pc-gB), 80% of BALB/c mice were completely protected and lesions were delayed in the remaining animals. Upon pc-gB vaccination, the animals developed both gB- and HSV-specific IgG Ab response and the isotype examination revealed a predominance of IgG2a. These mice also have low levels (1/16) of HSV-neutralizing Abs. Immune splenocytes obtained from pc-gB-immunized mice, when restimulated in vitro with HSV resulted in production of type 1 cytokines. Evidence for CD(8+)-mediated cytotoxic T lymphocyte response was equivocal. Protection could be adoptively transferred to nude mice recipients by CD4+ T cells from pc-gB-immunized mice but not by CD8+ T cells. Our results demonstrate that genetic immunization is a potent means of inducing protection against HSV and that the mechanism of immunity responsible for clearing virus from cutaneous sites is principally by CD4+ T cells. It is likely that these cells are Th1 cells because type 1 cytokines were the major cytokines detected upon in vitro Ag stimulation.

In vivo marginal adaptation of cast crowns luted with different cements

Large marginal crown discrepancies are deleterious. Although previous studies have examined casting seating in vitro, few have evaluated the effects of different luting cements on in vivo seating. Hence this in vivo study compared marginal discrepancies created by different cements on cast crowns. Tooth preparations were completed according to acceptable procedures on previously intact human molars that were severely periodontally compromised and scheduled for extraction. Castings were made by conventional techniques. The castings were randomly assigned to the following luting agents: zinc phosphate cement, resin-modified glass-ionomer cement, and the same resin-modified glass-ionomer cement with a dentinal bonding agent. After 6 months the teeth were carefully extracted, embedded, and sectioned, and vertical and horizontal discrepancies were measured. Analysis of variance revealed that all cements resulted in similar discrepancies. Vertical discrepancies were considerably greater than horizontal discrepancies, and the distributions of marginal discrepancies were skewed towards upper ranges.

Antiviral action of interferon-beta on Newcastle disease virus: selectivity to the hemagglutinin-neuraminidase gene expression

Interferon-beta (IFN-beta) strongly inhibited the expression of the hemagglutinin-neuraminidase (HN) gene of Newcastle disease virus (NDV), a paramyxovirus, in HeLa cells under the conditions where it did not affect the expression of the four upstream genes encoding the nucleocapsid protein, phosphoprotein, membrane protein and fusion protein. Even the downstream gene, encoding the large protein as well as the genome replication, appeared to be less susceptible to IFN-beta than the HN gene. This selective action of IFN-beta did not appear to be attributable to its well characterized antiviral mechanisms such as acceleration of RNA decay and translation inhibition. No similar down-regulation of a particular gene expression was found with another paramyxovirus, Sendai virus, or with a rhabdovirus, vesicular stomatitis virus, or seems to have been reported previously with any negative-strand RNA viruses. This new effect of IFN-beta thus suggests gene expression mechanism unique to NDV and may further lead to the discovery of a novel biochemical effect of IFN-beta.

[Relationship between elevated plasma endothelin-1 level and renal function in patients with diabetic nephropathy]

Plasma endothelin-1 (ET-1) level was measured with radioimmunoassay in 33 normal subjects and 92 patients with different stages of diabetic nephropathy, consisting of 35 cases of diabetes mellitus with normal urinary albumin excretion (DM), 22 cases of incipient diabetic nephropathy (IDN), 22 cases of overt diabetic nephropathy (ODN), 8 cases with azotemia (DNa) and 5 cases with uremia (DNu). The results showed that plasma ET-1 levels in DNa and DNu groups (30.24 +/- 1.93 ng/L and 36.38 +/- 3.62 ng/L respectively) were significantly higher than those in other groups (P < 0.05); ET-1 level in ODN group (20.50 +/- 0.93 ng/L) was significantly higher than those in DM and IDN groups (P < 0.001); ET-1 level in IDN group was also significantly higher than that in DM group (17.79 +/- 0.74 vs. 15.06 +/- 0.63 ng/L, P < 0.01); All the above values were significantly higher than that in normal subjects (7.08 +/- 0.22 ng/L) (P < 0.001). There was significant positive correlation between ET-1 level and HbA1c, systolic pressure, diastolic pressure, blood urea nitrogen, serum creatine, uAER and a significant negative correlation between ET-1 level and glomerular filtration rate. It is shown that progressive elevation of plasma ET-1 level is closely related with different stages of renal function impairment, suggesting strongly the role of ET-1 in the development and progression of diabetic nephropathy.