Analysis of large-volume DNA markers and polymerase chain reaction products by capillary electrophoresis in the presence of electroosmotic flow

We have demonstrated on-line concentration and separation of DNA in the presence of electroosmotic flow (EOF) using poly(ethylene oxide) (PEO) solutions. After injecting large-volumes DNA samples, PEO solutions entered a capillary filled with 400 mM Tris-borate (TB) buffers by EOF and acted as sieving matrices. DNA fragments stacked between the sample zone and PEO solutions. Because sample matrixes affected PEO adsorption on the capillary wall, leading to changes in EOF, migration time, concentration, and resolving power varied with the injection length. When injecting phiX174 RF DNA-HaeIII digest prepared in 5 mM Tris-HCl buffer, pH 7.0, at 250 V/cm, peak height increased linearly as a function of injection volume up to 0.9 microl (injection time 150 s). The sensitivity improvement was 100-fold compare to that injected at 25 V/cm for 10 s (0.006 microl). When injecting 1.54 microl of GeneScan 1000 ROX, the sensitivity improvement was 265-fold. The sensitivity improvement was 40-fold when injecting 0.17 microl DNA sample containing pBR 322/HaeIII, pBR 328/BglI, and pBR 328/HinfI digests prepared in phosphate-buffered saline. This method allows the analysis of polymerase chain reaction (PCR) products amplified after 17 cycles when injecting 0.32 microl (at 30 cm height for 300 s). The total analysis time was shorter (91.6 min) than that (119.6 min) obtained from injecting PCR products after 32 cycles for 10 s.

Optimizing separation conditions for polycyclic aromatic hydrocarbons in micellar electrokinetic chromatography

We report the separation of polycyclic aromatic hydrocarbons (PAHs) using 0.1% poly(ethylene oxide) (PEO) in micellar electrokinetic chromatography (MEKC). In the presence of PEO, adsorption of PAHs on the capillary wall was reduced, leading to better resolution and reproducibility. Effects of tetrapentylammonium iodide (TPAI), dextran sulfate (DS), methanol, and sodium lauryl sulfate (SDS) on the separation of PAHs were elucidated. In terms of resolution and speed, DS, compared to TPAI, is a better additive for separation of PAHs. When using 0.1% PEO solution containing 45% methanol, 50 mM SDS, and 0.02% DS, separation of 10 PAHs containing 2 to 5 benzene rings was accomplished in less than 12 min at 15 kV in a commercial CE system. The method has also been tested for separating seven PAHs with high quantum yields when excited at 325 nm using a He-Cd laser. Unfortunately, separation of the seven PAHs was not achieved and sensitivity diminished under the same conditions. To optimize sensitivity, resolution and speed, a stepwise technique in MEKC has been proposed. The seven PAHs were resolved in 35 min at 15 kV when separation was performed in 0.1% PEO solution containing 35 mM SDS, 40% methanol and 0.02% DS for 2 min, and subsequently in 0.1% PEO solution containing 20 mM SDS, 50% methanol, and 0.02% DS.

Regulation of electroosmotic flow and electrophoretic mobility of proteins for concentration without desalting

Proteins were concentrated and separated in 0.6% poly(ethylene oxide) (PEO) solution using a capillary filled with Tris-borate (TB) buffer prior to analysis and detected by laser-induced native fluorescence using a pulsed Nd:YAG laser. During the concentration and separation, PEO solution entered the capillary by electroosmotic flow. When proteins dissolved in high salts (phosphate-buffered saline) were separated using 0.6% PEO solution prepared in 200 mM TB buffer, pH 9.0, the limits of detection (LODs) at signal-to noise ratios=3 for carbonic anhydrase (CA) and alpha-lactalbumin (alpha-lac) were on the levels of sub microM and microM, respectively. The LOD values compared to those obtained in 38 mM TB buffer were relatively high, which is likely due to salt quenching, Joule heating and poor stacking. To improve sensitivity for analysis of proteins in high-conductivity media, two on-line concentration approaches without desalting were developed. When using a capillary filled with 1.5 M TB buffer, pH 10.0, and PEO solution prepared in 800 mM TB buffer, pH 9.0, the LOD values for CA and alpha-lac were 13.8 nM and 126.0 nM, respectively, which were about 4.7 and 11.2-fold sensitivity enhancements compared to those obtained by a conventional hydrodynamic injection (30 cm height for 10 s), respectively. The sensitivity was further improved by injecting a short plug of low pH buffer after protein injection using a capillary filled with 1.5 M TB buffer, pH 10.0, and PEO solution prepared in 400 mM TB buffer, pH 9.0. A linear relationship between the peak height and the injection volume up to 0.81 microl was obtained and the LOD values for CA and alpha-lac were down to 4.7 and 37.8 nM.

A new strategy for optimizing sensitivity, speed, and resolution in capillary electrophoretic separation of DNA

DNA separations were performed in poly(ethylene oxide) (PEO) solutions prepared in 100 mM Tris-boric acid (TB) buffers using a capillary filled with TB buffers with concentrations up to 2.5 M, pH 10.0. The electroosmotic flow (EOF) increased with increasing the concentration of TB buffers till 1.5 M as a result of decreasing PEO adsorption on the capillary wall. At high TB concentrations (> 1.5 M), the peaks corresponding to small DNA fragments (11 and 8 base pairs) became sharper and were detected. Relative standard deviations of the EOF coefficient and the migration times of the DNA fragments were all less than 1% using a capillary filled with TB buffers at concentrations higher than 1.5 M. When separations were performed at different pH values of PEO solutions and TB buffers, better results in terms of sensitivity, speed, and resolution were generally achieved. The fluorescence intensity of the 2176 bp fragment obtained at pH values of TB buffers/PEO solutions 10.0/8.2 was 27-fold of that at pH values 8.2/8.2. The enhancement was related to effects of pH and borate on fluorescence intensity, DNA conformation, stacking, and interactions with the capillary wall. Using a capillary filled with 400 mM TB buffers, pH 10.0, the separation of DNA (pBR 322/HaeIII digest, pBR 328/Bg/I digest and pBR 328/HinfI digest) in 1.5% PEO solutions prepared in 100 mM TB buffers, pH 9.0, at 375 V/cm was accomplished in less than 18 min.

Mechanisms of diethylstilbestrol-induced calcium movement in MG63 human osteosarcoma cells

The effect of the estrogen diethylstilbestrol (DES) on cytosolic free Ca(2+) levels ([Ca(2+)](i)) in MG63 human osteoblasts was explored by using fura-2 as a Ca(2+) indicator. DES at concentrations between 5--20 microM induced an immediate increase in [Ca(2+)](i) in a concentration-dependent manner with an EC(50) of 10 microM. Removing extracellular Ca(2+) reduced the Ca(2+) signal by 70%. Pretreatment with 50 microM La(3+) or 10 microM of nifedipine, verapamil and diltiazem did not change 20 microM DES-induced [Ca(2+)](i) increases. Addition of 3 mM Ca(2+) increased [Ca(2+)](i) in cells pretreated with 20 microM DES in Ca(2+)-free medium. Pretreatment with 1 microM thapsigargin (an endoplasmic reticulum Ca(2+) pump inhibitor) to deplete the endoplasmic reticulum Ca(2+) store partly inhibited 20 microM DES-induced Ca(2+) release, but addition of carbonylcyanide m-chlorophenylhydrazone (CCCP; a mitochondrial uncoupler) and thapsigargin together abolished DES-induced Ca(2+) release. Conversely, pretreatment with 20 microM DES abrogated CCCP- and thapsigargin-induced Ca(2+) release. Inhibition of phospholipase C activity with 2 microM U73122 did not alter 20 microM DES-induced Ca2+ release. Another estrogen 17beta-estradiol also increased [Ca(2+)](i) in a concentration-dependent manner with an EC50 of 7 microM. Together, the data indicate that in human osteoblasts, DES increased [Ca(2+)](i) via causing Ca(2+) release from both mitochondria and the endoplasmic reticulum in a phospholipase C-independent manner, and by causing Ca(2+) influx.

Fendiline, an anti-anginal drug, increases intracellular Ca2+ in PC3 human prostate cancer cells

BACKGROUND

The effects of the anti-anginal drug fendiline on intracellular Ca2+ concentrations ([Ca2+]i) in human PC3 prostate cancer cells were examined.

METHODS

[Ca2+]i was measured using the fluorescent dye fura-2.

RESULTS

Fendiline (0.5-100 microM) increased [Ca2+]i in a concentration-dependent manner. Ca2+ removal partly inhibited the Ca2+ signals. In Ca2+-free medium, pretreatment with 100 microM fendiline inhibited most of the [Ca2+]i increase induced by 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor), and pretreatment with thapsigargin abolished the fendiline-induced [Ca2+]i increases. Adding 3 mM Ca2+ increased [Ca2+]i in cells pretreated with 0.5-200 microM fendiline in Ca2+-free medium. Pretreatment with 1 microM U73122 to block the formation of inositol-1.4.5-trisphosphate (IP3) did not alter fendiline-induced internal Ca2+ release.

CONCLUSIONS

The anti-anginal drug fendiline induced internal Ca2+ release and external Ca2+ entry. Because prolonged increases in [Ca2+]i may lead to cell injury and death, the long-term effect of fendiline on the function of prostate cancer cells should be investigated.

Separation of dsDNA in the presence of electroosmotic flow under discontinuous conditions

Separations of phiX-174/HaeIII DNA restriction fragments have been performed in the presence of electroosmotic flow (EOF) using five different polymer solutions, including linear polyacrylamide (LPA), poly(ethylene oxide) (PEO), hydroxypropylcellulose (HPC), hydroxyethylcellulose (HEC), and agarose. During the separation, polymer solutions entered the capillary by EOF. When using LPA solutions, bulk EOF is small due to adsorption on the capillary wall. On the other hand, separation is faster and better for the large DNA fragments (> 872 base pairs, bp) using derivative celluloses and PEO solutions. Several approaches to optimum resolution and speed by controlling EOF and/or altering electrophoretic mobility of DNA have been developed, including (i) stepwise changes of ethidium bromide (0.5-5 microg/mL), (ii) voltage programming (125-375 V/cm), (iii) use of mixed polymer solutions, and (iv) use of high concentrations of Tris-borate (TB) buffers. The DNA fragments ranging from 434 to 653 bp that were not separated using 2% PEO (8,000,000) under isocratic conditions have been completely resolved by either stepwise changes of ethidium bromide or voltage programming. Compared to PEO solutions, mixed polymer solutions prepared from PEO and HEC provide higher resolving power. Using a capillary filled with 600 mM TB buffers, pH 10.0, high-speed (< 15 min) separation of DNA (pBR 322/HaeIII digest, pBR 328/ Bg/l digest and pBR 328/Hinfl digest) has been achieved in 1.5% PEO.

Effects of the antianginal drug fendiline on Ca2+ movement in hepatoma cells

This study investigated the effect of the anti-anginal drug, fendiline, on intracellular free Ca2+ levels ([Ca2+]i) in HA/ 22 human hepatoma cells by using fura-2 as a fluorescent Ca2+ dye. Fendiline (1-100 microM) increased [Ca2+]i with an EC50 of 25 microM. Removal of extracellular Ca2+ reduced the [Ca2+]i signals by 51 +/- 5%. Fendiline (10 microM)-induced Ca2+ release was abolished by pretreatment with 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor). Inhibition of phospholipase C with 2 microM 1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122) did not alter 10 microM fendiline-induced Ca2+ release. Several other calmodulin antagonists, such as phenoxybenzamine (100-200 microM), trifluoperazine (5-50 microM), and fluphenazine-N-chloroethane (2-100 microM), had no effect on [Ca2+]i. Together, it was found that fendiline increased [Ca2+]i in human hepatoma cells by discharging Ca2+ from the endoplasmic reticulum in an inositol 1,4,5-trisphosphate-independent manner and by inducing Ca2+ entry. This effect of fendiline does not appear to be via antagonism of calmodulin.

Clomiphene, an ovulation-inducing agent, causes [Ca2+]i increases in human osteoblast-like cells

The effect of clomiphene, an ovulation-inducing agent, on cytosolic free Ca2+ levels ([Ca2+]i) in MG63 human osteosarcoma cells was explored by using fura-2 as a Ca2+ indicator. Clomiphene at concentrations between 5-75 microM increased [Ca2+]i in a concentration-dependent manner with an EC50 of 50 microM. The [Ca2+]i signal consisted of an initial rise and a sustained phase. Ca2+ removal reduced the Ca2+ signal by 40+/-10%. The [Ca2+]i increase induced by 50 microM clomiphene was inhibited by 80+/-5% by 10 microM nifedipine, but was insensitive to 50 microM La3+ or 10 microM verapamil. In Ca2+-free medium, pretreatment with 50 microM brefeldin A (to disrupt the Golgi complex Ca2+ store), 1 microM thapsigargin (to inhibit the endoplasmic reticulum Ca2+ pump), and carbonylcyanide m-chlorophenylhydrazone (CCCP; to uncouple mitochondria) inhibited 51+/-3% of 50 microM clomiphene-induced Ca2+ release; conversely, pretreatment with 50 microM clomiphene abolished the [Ca2+]i increase induced by thapsigargin, CCCP, and brefeldin A. The Ca2+ release-induced by 50 pM clomiphene was unchanged by inhibition of phospholipase C with 2 microM 1-(6-((17beta-3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione (U73122). Collectively, the results suggest that clomiphene increased [Ca2+]i, in osteoblast-like cells, by releasing intracellular Ca2+ in a phospholipase C-independent manner and by causing nifedipine-sensitive Ca2+ influx.

Tamoxifen-induced Ca2+ mobilization in bladder female transitional carcinoma cells

This study examined the effect of tamoxifen, an anti-breast cancer drug, on Ca2+ handling in bladder female transitional cancer cells. Changes in cytosolic free Ca2+ levels were recorded by using the Ca2+-sensitive dye fura-2. In a dose-dependent manner, tamoxifen induced intracellular free Ca2+ concentrations ([Ca2+]i) increases between 5 and 20 microM with an EC50 of 10 microM. External Ca2+ removal reduced the response by 60+/-6%. Addition of 3 mM Ca2+ caused a [Ca2+]i increase after pretreatment with 10 microM tamoxifen in Ca2+-free medium. In Ca2+-free medium, pretreatment with 10 microM tamoxifen abolished the [Ca2+]i increase induced by 1 microM thapsigargin, an endoplasmic reticulum Ca2+ pump inhibitor. Conversely, pretreatment with 1 microM thapsigargin prevented tamoxifen from releasing more Ca2+. Inhibition of phospholipase C-dependent inositol 1,4,5-tris-phosphate formation with 2 microM U73122 did not alter 10 microM tamoxifen-induced Ca2+ release. The [Ca2+]i increase induced by 5 microM tamoxifen was not altered by 10 microM La3+, nifedipine, verapamil, and diltiazem. Collectively, it was found that tamoxifen increased [Ca2+]i in bladder cancer cells by releasing Ca2+ from the endoplasmic reticulum Ca2+ stores in a manner independent of phospholipase C activity, and by inducing Ca2+ entry from external medium.

Effect of fluoxetine on intracellular Ca2+ levels in bladder female transitional carcinoma (BFTC) cells

The effect of the antidepressant fluoxetine on Ca2+ signaling in cultured cells was largely unknown. The effect of various concentrations of fluoxetine on [Ca 2+] i in populations of bladder female transitional cancer (BFTC) cells was evaluated by using fura-2 as a Ca2+ probe. Fluoxetine increased [Ca 2+] i concentration dependently (20-100 microM) with an EC50 value of 30 microM. The response was inhibited by 50-60% on extracellular Ca2+ removal. In Ca2+ -free medium, pretreatment with 1 microM thapsigargin (an inhibitor of the endoplasmic reticulum Ca2+ pump) abolished 50 microM fluoxetine-induced Ca2+ release; whereas pretreatment with fluoxetine did not alter the thapsigargin-induced Ca2+ response. Addition of 3 mM Ca2+ increased [Ca 2+] i after pretreatment with 50 microM fluoxetine in Ca2+ -free medium, suggestive of fluoxetine-induced capacitative Ca2+ entry. Suppression of inositol 1,4,5-trisphosphate formation by 2 microM U73122 (a phospholipase C inhibitor) did not affect 50 microM fluoxetine-induced Ca2+ release. Collectively, this study shows that fluoxetine increased [Ca 2+] i in bladder cancer cells in a concentration-dependent fashion, by releasing Ca2+ from thapsigargin-sensitive Ca2+ stores in an IP3-independent manner, and by inducing Ca2+ influx from extracellular medium.

Direct vertical electroelution of protein from a PhastSystem band for mass spectrometric identification at the level of a few picomoles

An electroelution apparatus prototype of a new design was constructed. In that design, the electric field passes vertically through the protein band located on a horizontal (PhastSystem) minigel polymerized on a net of Gel-Fix (Serva). A simple, home-made apparatus allows for electroelution of protein bands at the level of a few picomoles and their identification, after concentration, by matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The technique is applicable to one-dimensional (1-D) or two-dimensional (2-D) gels of any size, but has been exemplified only by application to 1-D minigels to demonstrate the lower limits of protein load of the method. When in the course of further development of the prototype it will be combined with a modification to two dimensions of the electroelution mechanism under computer control of the high-performance gel electrophoresis apparatus (formerly of LabIntelligence), the new design appears uniquely qualified for an automated spot elution from 2-D gels under avoidance of gel sectioning.

Fendiline-Induced Ca2+ movement in A10 smooth muscle cells

The effect of fendiline, an anti-anginal drug, on cytosolic free Ca2+ levels ([Ca2+]i) in A10 smooth muscle cells was explored by using fura-2 as a Ca2+ indicator. Fendiline at concentrations between 10-50 microM increased [Ca2+]i in a concentration-dependent manner with an EC50 of 20 microM. External Ca2+ removal reduced the Ca2+ signal by 75%. Addition of 3 mM Ca2+ increased [Ca2+]i in cells pretreated with fendiline in Ca2+-free medium. The 50 microM fendiline-induced [Ca2+]i increase in Ca2+-containing medium was inhibited by 10 microM of La3+, nifedipine, or verapamil. In Ca2+-free medium, pretreatment with 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor) to deplete the endoplasmic reticulum Ca2+ store partly inhibited 50 microM fendiline-induced Ca2+ release; whereas pretreatment with 50 microM fendiline abolished 1 microM thapsigargin-induced Ca2+ release. Inhibition of phospholipase C activity with 2 microM U73122 did not alter 50 microM fendiline-induced Ca2+ release. Incubation with 50 microM fendiline for 10-30 min decreased cell viability by 10-20%. Together, the findings indicate that in smooth muscle cells fendiline induced [Ca2+]i increases. Fendiline acted by activating Ca2+ influx via L-type Ca2+ channels, and by releasing internal Ca2+ in a phospholipase C-independent manner. Prolonged exposure of cells to fendiline induced cell death.

Electroelution of proteins from bands in gel electrophoresis without gel sectioning for the purpose of protein transfer into mass spectrometry: elements of a new procedure

Electroelution of protein bands from a gel has advantages over the competitive common technique requiring gel sectioning with respect to yield, speed and the potential for computer-controlled application to multicomponent two-dimensional (2-D) gels. The electroelution design for the commercial high-performance gel electrophoresis (HPGE) apparatus represented the most advanced technique to date until the recent discontinuation of its production. The present report serves to summarize the necessary design elements for the purpose of renewing and further developing the electroelution technique. A rudimentary technique is presented by which the electroeluate is collected in a glass tube superimposed on a reversibly stained gel band and connected to an anolyte reservoir. Although the stain used is insufficiently sensitive, the technique allowed for the qualitative verification of its usefulness in the transfer of the electroeluate into mass spectrometry.

Characterization of histamine-induced increases in intracellular free Ca2+ concentrations in Chang liver cells

The effect of histamine on intracellular free Ca2+ levels ([Ca2+]i) in Chang liver cells were investigated by using fura-2 as a Ca2+ dye. Histamine (0.2-50 microM) increased [Ca2+]i in a concentration-dependent manner with an EC50 value of 0.8 microM. The [Ca2+]i response comprised an initial rise, a slow decay, and a sustained phase. Extracellular Ca2+ removal inhibited 50% of the maximum [Ca2+]i signal and abolished the sustained phase. After pretreatment with 5 microM histamine in Ca2+-free medium for 4 min, addition of 3 mM Ca2+ induced a [Ca2+]i increase with a magnitude 7-fold greater than control. In Ca2+-free medium, after treatment with 1 microM thapsigargin (an endoplasmic reticulum Ca2+ pump inhibitor), 5 microM histamine failed to increase [Ca2+]i. Histamine (5 microM)-induced intracellular Ca2+ release was abolished

Dynamic modification of the capillary wall for electrophoretic separations of small ions

Separations of small ions were carried out under nonequilibrated conditions using capillaries treated with NaOH, HCl, or tris(hydroxymethyl)aminomethane (Tris) prior to analysis. For separations of benzoic acid isomers or acids and amines under weakly acidic conditions, capillaries flushed with 0.1 M NaOH and subsequently with running buffers prior to analysis were used. Separations of six benzoic acid isomers were accomplished in 4 min in 1 mM phosphate buffers, pH 4.01, containing 2.5 mM hydroxypropyl-beta-cyclodextrin. Without additives, the separation of biological amines and acids were also achieved in 10 min at pH 4.01. Capillaries treated with 0.1 M HCl prior to analysis were tested in separations of six phenols in 5 mM Tris solutions at pH 7.0. As a result of small electrophoretic mobilities of phenols against a small electroosmotic flow, resolution was optimized. We also found that reproducibility was improved using capillaries treated with HCl. The relative standard deviations of migration mobility of phenols were less than 1%, which were smaller than those obtained using capillaries treated with 0.1 M NaOH or Tris.

On-line concentration and separation of proteins by capillary electrophoresis using polymer solutions

Proteins were separated in 0.6% poly(ethylene oxide) (PEO) solutions using a capillary filled with buffers prior to analysis and were detected by laser-induced native fluorescence using a pulsed Nd:YAG laser. PEO solutions entered the capillary by electroosmotic flow (EOF) during the separation. The composition and concentration of the buffer affected the adsorption of PEO molecules on the capillary surface and, consequently caused changes in the EOF. Short separation times (< 7 min) were achieved on a sample solution of five proteins in a 0.6% PEO solution containing 5 microg/mL ethidium bromide using a capillary pre-filled with 100 mM TRIS-borate (TB) buffers (pH 10,0). We also extended this method for on-line concentration and separation of proteins. Proteins dissolved in low-conductivity media stacked in both TB buffers and in PEO solutions. The peak height was proportional to the injection volume up to 2.1 microL using an 80-cm capillary filled with 400 mM TB buffers. Using large injection volumes (2.1 microL), we achieved a limit of detection (S/N = 3) of 31 pM for carbonic anhydrase, which was a 1696-fold sensitivity enhancement compared to a conventional injection method (1 kV for 10 s). In high-conductivity media (urine matrix), stacking occurred at the boundary between the sample zone and PEO solutions. A urine sample without any pretreatment was analyzed, and after stacking, several peaks were detected. Spiking the urine sample with human serum albumin (HSA) affected the fluorescent intensity of some analytes as a result of interaction with HSA.

Effect of ionic strength, pH and polymer concentration on the separation of DNA fragments in the presence of electroosmotic flow

DNA separations in the presence of electroosmotic flow (EOF) using poly(ethylene oxide) (PEO) solutions have been demonstrated. During the separations, PEO entered capillaries filled with Tris-borate (TB) free buffers by EOF and acted as sieving matrices. We have found that ionic strength and pH of polymer and free solutions affect the bulk EOF and resolution differently from that in capillary zone electrophoresis. The EOF coefficient increases with increasing ionic strength of the free TB buffers as a result of decreases in the adsorption of PEO molecules. In contrast, the bulk EOF decreases with increasing the ionic strength of polymer solutions using capillaries filled with high concentrations of free TB buffers. Although resolution values are high due to larger differential migration times between any two DNA fragments in a small bulk EOF using 10 mM TB buffers, use of a capillary filled with at least 100 mM TB free buffers is suggested for high-speed separations. On the side of PEO solutions, 1.5% PEO solutions prepared in 100 to 200 mM TB buffers are more proper in terms of resolution and speed. The separation of DNA markers V and VI was accomplished less than 29 min in 1.5% PEO solutions prepared in 100 mM TB buffers, pH 7.0 at 500 V/cm using a capillary filled with 10 mM free TB buffers, pH 7.0.

On-column preconcentration and separation of DNA fragments using polymer solutions in the presence of electroosmotic flow

We demonstrated DNA preconcentration and separation in the presence of electroosmotic flow (EOF) using poly(ethylene oxide) (PEO) solutions. After injecting large volumes of DNA samples into a capillary filled with free tris(hydroxymethyl)aminomethane (Tris)-borate (TB) buffers, PEO solutions entered the capillary by EOF and acted as sieving matrices. In contrast to conventional methods (in the absence of EOF), controlling the EOF was also useful for resolution optimization. We have found that PEO adsorption on the capillary wall was more pronounced when low ionic strength buffers were used. Thus, the EOF decreased with increasing injection length, which led to longer migration times and changes in resolution and stacking efficiency. All resolution values were higher than 1.5 when 1.0 microg/mL DNA samples were injected at 240 V/cm for 60 s (0.67 microL). In addition, as low as 0.015 microg/mL DNA samples (an about 66-fold increase in sensitivity) were detected when the injection was performed at 250 V/cm for 60 s.

Lipid-rich diffuse malignant mesothelioma: a case report

An 80-year old man presented with shortness of breath and was found to have a large right pleural effusion. Cytology of the pleural fluid showed atypical papillary clusters of epithelioid cells. Multiple white-yellow nodules studding the pleural surfaces were seen at thoracoscopy, and biopsies showed solid and papillary clusters of large epithelioid cells with abundant cytoplasm filled with clear vacuoles. Special stains and electron microscopic findings indicated that the tumor was a diffuse malignant mesothelioma with numerous intracytoplasmic lipid vacuoles. Fat stain may be useful at time of frozen section for a pleural-based tumor with vacuolated cells, and the presence of lipid vacuoles in a pleural-based tumor does not exclude diffuse malignant mesothelioma.

Risk factors of mortality in perforated peptic ulcer

OBJECTIVE

To assess the risk factors that influence mortality from perforated peptic ulcer.

DESIGN

Retrospective study.

SETTING

General hospital, Taiwan.

SUBJECTS

179 patients who had their perforated peptic ulcers operated on and who had minimum follow-up of one year.

MAIN OUTCOME MEASURES

Mortality.

RESULTS

The overall mortality was 15% (26/179). Of the 26 patients who died, the cause of death was uncontrolled systemic infection in 21 (81%), hypovolaemic shock in 2, and fatal arrhythmia and heart failure in 1 each. 15 of the patients who died of sepsis did not have fulminant abdominal sepsis. Most deaths occurred early after operation, (range 1-96 days). Old age, preoperative shock, and type of operation seemed to be related to these deaths on univariate analysis, but multivariate analysis showed that coexisting medical illness, delayed treatment, and low albumin concentration were independent risk factors for mortality.

CONCLUSIONS

To improve the result of treatment of perforated peptic ulcer, the diagnosis and treatment should not be delayed, the associated medical illnesses should be treated, and nutritional support should be given.

Iteration-free fractal image coding based on efficient domain pool design

The domain pool design is one of the dominant issues which affect the coding performance of fractal image compression. In this paper, we employ the LBG algorithm and propose a block averaging method to design the efficient domain pools based on a proposed iteration-free fractal image codec. The redundancies between the generated domain blocks are reduced by the proposed methods. Therefore, we can obtain the domain pools that are more efficient than those in the conventional fractal coding schemes and thus the coding performance is improved. On the other hand, the iteration process in the conventional fractal coding scheme not only requires a large size of memory and a high computation complexity but also prolongs the decoding process. The proposed iteration-free fractal codec can overcome the problems above. In computer simulation, both the LBG-based and block-averaging methods for the domain pool design in the proposed iteration free scheme achieve excellent performances. For example, based on the proposed block-averaging method, the decoded Lena image has at least a 0.5 dB higher PSNR (under the same bit rate) and an eight-time faster decoding speed than the conventional fractal coding schemes that require iterations.

Analysis of prognostic factors in Chinese women with breast cancer in southern Taiwan

BACKGROUND

We conducted a retrospective review of all early-stage breast cancer patients treated at the Veterans General Hospital-Kaohsiung to determine overall and disease-free survival rates, and to evaluate prognostic factors for these outcomes.

METHODS

During the period of October, 1990, to December, 1997, 332 patients with early-stage breast cancer were treated at our institution. Cox's multivariate regression analysis was used to select prognostic factors significant for overall survival and disease-free survival.

RESULTS

The survival rate for breast cancer patients was 88.35% at five years. Prognostic factors predicting breast cancer mortality included poorly differentiated histologic grade, four or more lymph nodes positive for metastasis and negative progesterone-receptor status. For disease recurrence, prognostic factors included positive nodes, aneuploidy and poorly differentiated histologic grading.

CONCLUSIONS

We conclude that a combination of lymph node status, DNA ploidy, histologic grading and progesterone-receptor status help to evaluate the possible outcomes for patients with breast cancer and to plan for optimal therapy.

Primary non-Hodgkin's lymphoma of the breast: breast conservation therapy in two patients

We report two patients with primary non-Hodgkin's lymphoma of the breast who were treated with breast conservation therapy. These two patients were diagnosed with primary breast lymphoma by fine-needle aspiration cytology and underwent tumorectomy followed by adjuvant chemoradiation therapy. Follow-up studies showed that the two patients were free of disease for two and three years, respectively. To date, there exists no therapeutic standard for this disease and there is no survival advantage for patients who undergo radical mastectomy. Despite the rarity of lymphoma in the breast, a preoperative accurate diagnosis is essential so that unnecessary, extended breast ablation or delayed treatment is avoided. Cytologic diagnosis of breast lymphoma is an easy procedure and provides guidance for appropriate preoperative management. Early diagnosis combined with breast conservation therapy and systemic adjuvant therapy results in a favorable outcome for patients with breast lymphoma.

Indirect detection of organic acids in non-aqueous capillary electrophoresis

Non-aqueous capillary electrophoresis (NACE) with indirect detection has been applied to the determination of fatty acids (FAs) and ascorbic acid (AA), respectively. C2-C18 FAs have been separated in less than 12 min using 8-hydroxy-7-iodoquinoline sulfonic acid as chromophores in NACE with indirect absorbance. The dissociation constant (pKa) values of C8-C18 FAs obtained from the slope of the linear plot -log [(mu 0/mu)-1] vs. pH, using 20% isopropanol and 40% acetonitrile as the organic modifier in NACE, are all above about two units than those obtained in aqueous solution. NACE with indirect laser-induced fluorescence, using merocyanine 540 (MC540) as fluorophores, has been performed to the analysis of AA and its stereoisomer, isoascorbic acid (IAA), and the limits of detection of AA and IAA are 0.30 microM and 0.17 microM, respectively. This method has been applied to the determination of AA in a lemon juice spiked with IAA as the internal standard in less than 3 min and its concentration is 76.7 +/- 0.4 mM.