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PubMed2005

Rheological, mucoadhesive and release properties of pluronic F-127 gel and pluronic F-127/polycarbophil mixed gel systems.

This study was designed to combine the mucoadhesive property of Noveon and the thermosensitive property of Pluronic F-127 into one gel system. A rheological study of Pluronic aqueous sols (10-35%), Noveon gels (0.5-2%) and of mixed gels containing Pluronic (10-17.5%) and polycarbophil (0.5-2.5%) was conducted at different temperatures (15-35 degrees C). The viscosity of Pluronic sols increased with an increase in temperature and the mixed gels had thermoreversible property. The viscosity of mixed gels was higher than that of the Pluronic sols containing only Pluronic because of the increase in total polymer concentration. No interaction was found between -COOH groups of Noveon and Pluronic molecules at the studied concentrations of polymers; the viscosity of mixed gels containing un-neutralized Noveon was lower than that of the neutralized mixed gels. The effect of Pluronic F-127 on the mucoadhesive property of Noveon was investigated. The mucoadhesive properties of Pluronic and Noveon gels were compared by a force of detachment test. It was found that Pluronic and Noveon gels showed approximately the same mucoadhesive strength. However, there were significant differences in the viscosity of Noveon and Pluronic gels. The adhesive force of the mixed gel was almost same as that of the Noveon gel. The Pluronic did not affect the adhesive power of Noveon and the increased viscosity did not affect the bioadhesive force of the mixed gels. In spite of increasing viscosity of the gel, the percentage of released model material (mannitol) increased with increasing temperature. This is based on the previously reported observation that the interaction between the Pluronic molecules squeezed mannitol molecules out of the polymer chains. The mannitol release obeyed zero-order kinetics and the flux values of mixed gels at 15 and 35 degrees C were very similar. The Noveon chains among Pluronic chains probably hindered the diffusion of mannitol molecules and the release was thus controlled by Noveon. The combination of a thermosensitive polymer like Pluronic and a bioadhesive polymer like Noveon appears promising from a pharmaceutical viewpoint. These gel systems may find use in the development of bioadhesive, thermosensitive and controlled release formulations.

Acrylic Resins↗
PubMed2004

Effects of gel composition on the radiation induced density change in PAG polymer gel dosimeters: a model and experimental investigations.

Due to a density change that occurs in irradiated polyacrylamide gel (PAG), x-ray computed tomography (CT) has emerged as a feasible method of performing polymer gel dosimetry. However, applicability of the technique is currently limited by low sensitivity of the density change to dose. This work investigates the effect of PAG composition on the radiation induced density change and provides direction for future work in improving the sensitivity of CT polymer gel dosimetry. A model is developed that describes the PAG density change (delta(rho)gel) as a function of both polymer yield (%P) and an intrinsic density change, per unit polymer yield, that occurs on conversion of monomer to polymer (delta(rho)polymer). %P is a function of the fraction of monomer consumed and the weight fraction of monomer in the unirradiated gel (%T). Applying the model to experimental CT and Raman spectroscopic data, two important fundamental properties of the response of PAG density to dose (delta(rho)gel dose response) are discovered. The first property is that delta(rho)polymer)depends on PAG %C (cross-linking fraction of total monomer) such that low and high %C PAGs exhibit a higher deltarho(polymer)than do more intermediate %C PAGs. This relationship is opposite to the relationship of polymer yield to %C and is explained by the effect of %C on the type of polymer formed. The second property is that the delta(rho)gel dose response is linearly dependent on %T. From the model, the inference is that, at least for %T < or = 2%, monomer consumption and delta(rho)polymer depend solely on %C. In terms of optimizing CT polymer gel dosimetry for high sensitivity, these results indicate that delta(rho)polymer can be expected to vary with each polymer gel system and thus should be considered when choosing a polymer gel for CT gel dosimetry. However, delta(rho)polymerand %P cannot be maximized simultaneously and maximizing %P, by choosing gels with intermediate %C and high %T, is found to have the greatest impact on increasing the sensitivity of PAG density to dose. As such, future research into new gel formulations for high sensitivity CT polymer gel dosimetry should focus on gels that exhibit an intrinsic density change and maximizing polymer yield in these systems.

Acrylic Resins↗
PubMed2001

Mass spectrometric imaging of immobilized pH gradient gels and creation of "virtual" two-dimensional gels.

We have developed a matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) based technique for the detection of intact proteins directly from immobilized pH gradient gels (IPGs). The use of this technique to visualize proteins from IPGs was explored in this study. Whole cell Escherichia coli extracts of various loadings were separated on IPGs. These IPGs were processed to remove contaminants and to achieve matrix/analyte cocrystallization on the surface of the gel. Mass spectra were acquired by scanning the surface of the gel and were assimilated into a "virtual" two dimensional (2-D) gel. This virtual 2-D gel is analogous to a "classical" 2-D gel, except that the molecular weight information is acquired by mass spectrometry rather than by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). This mass spectrometry (MS) based technology exemplifies a number of desirable characteristics, some of which are not attainable with classical two-dimensional electrophoresis (2-DE). These include high sensitivity, high reproducibility, and an inherently higher resolution and mass accuracy than 2-D gels. Furthermore, there is a difference in selectivity exhibited between virtual 2-D gels and classical 2-D gels, as a number of proteins are visible in the virtual gel image that are not present in the stained gels and vice versa. In this report, virtual 2-D gels will be compared to classical 2-D gels to illustrate these features.

Bacterial Proteins↗
PubMed2003

A comparison of 15% azelaic acid gel and 0.75% metronidazole gel in the topical treatment of papulopustular rosacea: results of a randomized trial.

OBJECTIVE: To compare the efficacy and safety of a novel formulation of 15% azelaic acid gel (Finacea; Berlex Laboratories, Inc, Montville, NJ) with 0.75% metronidazole gel (MetroGel; Galderma Laboratories LP, Fort Worth, Tex) as topical therapy for moderate, papulopustular facial rosacea. DESIGN: Multicenter, double-blind, randomized, parallel-group study. SETTING: Thirteen US centers. PATIENTS: A total of 251 patients with papulopustular rosacea with persistent erythema and telangiectasia. INTERVENTIONS: Patients were randomized to receive azelaic acid gel or metronidazole gel twice daily for 15 weeks. MAIN OUTCOME MEASURES: Nominal and percent change in inflammatory lesion count, change in erythema and telangiectasia severity ratings, investigator's global assessment of rosacea, and investigator's and patient's overall improvement ratings. RESULTS: Azelaic acid gel was superior to metronidazole gel in reduction of mean nominal lesion count (-12.9 vs -10.7, respectively) (P =.003) and mean percent decrease in inflammatory lesions (-72.7% vs -55.8%, respectively) (P<.001). With respect to erythema severity, 56% of azelaic acid gel-treated patients were rated improved vs 42% of metronidazole gel-treated patients (P =.02). The effectiveness of metronidazole gel on these variables seemed to plateau after week 8, whereas azelaic acid gel demonstrated progressive improvement through week 15. Neither treatment had a clinically appreciable effect on telangiectasia. Both the investigator's global assessment (P =.02) and overall assessment of improvement (P =.005) showed a significant therapeutic advantage for azelaic acid gel. Azelaic acid gel also scored higher on the patient's overall assessment of efficacy. Both treatments were rated as having high cosmetic acceptability. No serious or systemic treatment-related adverse events were reported in either group. CONCLUSION: Use of 15% azelaic acid gel twice daily for 15 weeks demonstrated significant superiority over using 0.75% metronidazole gel in improving principal signs of rosacea (inflammatory lesions and erythema).

Administration, Topical↗
PubMed1990

Giant two-dimensional gel electrophoresis: methodological update and comparison with intermediate-format gel systems.

Two-dimensional (2-D) gel electrophoresis methods for separating complex mixtures of proteins have not changed fundamentally since their original description in the late 1970's. Nevertheless, 2-D gel resolution has improved substantially as a result of a series of incremental modifications. One of these was the development of the "giant-gel" format, using gels measuring at least 30 x 30 cm to provide the highest resolution 2-D gel system available. As originally described, this procedure has several important limitations: it requires custom-built equipment; it is expensive in terms of time, reagents, film and support matrices; and it generates gels which are difficult to manupulate, particularly for silver staining. This report describes modifications in the giant gel procedure to permit use of a commercially available gel apparatus and to obtain giant gels of improved mechanical strength suitable for silver staining. The resolution of giant gels is compared with that obtained using two systems currently being marketed for use by laboratories performing large numbers of 2-D gel analyses. The smaller format gels resolved fewer proteins, by 30-40%, compared with the giant gels. This difference in resolving power suggests that giant gels will continue to be useful in selected applications.

Autoradiography↗
PubMed1996

[Comparative study of the efficacy and tolerability of 0.1 and 0.03 p.100 adapalene gel and 0.025 p.100 tretinoin gel in the treatment of acne].

INTRODUCTION: Adapalene is a new chemical entity with retinoid activity. PATIENTS AND METHODS: 0.1 p. 100 adapalene gel (Différine gel), 0.03 p. 100 adapalene gel and a commercially available 0.025 p. 100 tretinoin gel (Aberel gel) were compared in 89 male and female patients with acne. RESULTS: Inflammatory, non inflammatory, total lesion counts, and the global facial acne grade regularly decreased as a function of time in the three treatment groups. No statistically or clinicaly significant differences were observed for these parameters between 0.1 p. 100 adapalene gel and 0.025 p. 100 tretinoin gel following a 12-week treatment. Conversely, both of these gels were significantly more effective than 0.03 p. 100 adapalene gel with regards to inflammatory and total lesion counts, and the global facial acne grade. The differences of efficacy seen between both adapalene gels demonstrate a dose-dependent activity of the drug in the topical treatment of acne. The three products induced retinoid-like skin irritation with significant differences in intensity in favour of adapalene for erythema, dryness, scaling and burning after application and in favour of tretinoin for persistent burning. No treatment-related medical events were reported and adapalene plasma levels were lower than 0.15 ng/ml (limit of detection of the analytical method). CONCLUSIONS: The topical treatment of acne with adapalene gels was found to be safe and effective, with a dose-related response. The efficacy of 0.1 p. 100 adapalene gel and of 0.025 p. 100 tretinoin gel are not different but skin tolerance of 0.1 p. 100 adapalene gel is superior.

Acne Vulgaris↗
PubMed1996

An exactly solvable Ogston model of gel electrophoresis: I. The role of the symmetry and randomness of the gel structure.

The Ogston-Morris-Rodbard-Chrambach model (OMRCM) of gel electrophoresis assumes that the mobility (mu) of charged particles is directly proportional to the fractional volume (f) of the gel that is available to them. Many authors have studied the fractional volume f in detail for various particle shapes, but the original assumption, that mu sf, has not been scrutinized seriously. In fact, this geometrical model of electrophoresis does not take into account the connectivity of the gel pores or the precise gel architecture. Recently (G. W. Slater and H. L. Guo, Electrophoresis 1995, 16, 11-15) we developed a Monte Carlo computer simulation algorithm to study the electrophoretic motion of simple particles in gels in the presence of fields of arbitrary strength. Our preliminary results indicated that the mobility and the fractional volume were not generally proportional to one another. In this article, we show how to calculate, in the limit where the field intensity is vanishingly small, the exact electrophoretic mobility of particles in any type of gel in two or more dimensions. Our results, presented here for some simple two-dimensional systems, indicate that a particle can have different electrophoretic mobilities in gels in which it has access to the same fractional available volume f. The curvature of the Ferguson plot is shown to be related to the symmetry and the degree of randomness that characterize the gel. We also demonstrate that the OMRCM is, in fact, a mean field approximation that corresponds to a uniform, annealed gel. We thus conclude that the relation between the electrophoretic mobility and the gel concentration (C) is a delicate function of the gel architecture, and that one needs more than the fractional volume f to fully characterize the transport properties of migrating particles in separation media. Exact relationships between the mobility mu and the gel concentration C are given for our model gels.

Animals↗
PubMed1988

Skin tumorigenesis and carcinogenesis studies with 7,12-dimethylbenz[a]anthracene, ultraviolet light, benzoyl peroxide (Panoxyl gel 5%) and ointment gel.

In a previous paper it was demonstrated on hairless mouse skin that 5% benzoyl peroxide (BP) in a gel (Panoxyl), or gel alone, applied just before UV radiation had a protective effect against UV-induced tumorigenesis, but both enhanced 7,12-dimethylbenz[a]anthracene (DMBA)-induced tumorigenesis. Groups of hairless (hr/hr) mice were therefore given ultraviolet (UV) irradiation with or without additional treatment with Panoxyl or gel in order to see whether Panoxyl or the gel given long time before, or after, irradiation influenced UV-induced tumorigenesis. Consequently, in some animals Panoxyl or gel was applied in the evening and the mice were irradiated the next day; in others, Panoxyl or gel was applied 5-30 min after UV irradiation. Enhancement of DMBA-induced carcinogenesis in hr/hr mice by the gel alone (assumed to be inert) was unexpected, and hence one group of hr/hr mice was first given 51.2 micrograms DMBA in acetone and thereafter treated twice a week with gel alone. All mice were tested and observed for skin tumors and other lesions for 52 weeks. Neither Panoxyl nor gel influenced UV tumorigenesis or carcinogenesis under these experimental conditions. In hr/hr mice there was this time no enhancement of DMBA-induced tumorigenesis by the gel, and a slight reduction of carcinogenesis. In addition, several groups of SENCAR mice (which have been bred for high sensitivity to skin carcinogenesis) were also treated, with acetone alone, with a single application of DMBA alone, with Panoxyl alone, or with DMBA followed by treatment with the ointment gel or with Panoxyl twice a week throughout the experiment. In SENCAR mice there was no difference between the results of treatment with DMBA followed by Panoxyl, or DMBA followed by gel, and both substances tended to reduce the tumorigenicity of DMBA alone, and Panoxyl or gel showed no tumorigenicity of their own. The total dose of UV used in this study was lower than that used in the first study. This reduction in dose significantly increased the tumorigenic effect of UV.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1989

[Study on the physico-chemical properties of fluoride gel in application of freeze-drying gelatin gel method (tray method)].

As a means of studies of securing freeze-drying method by application of tray for prevention of white spots, decalcification and secondary caries of enamel, which may develop during and after orthodontic treatment, comparison and review were made on physico-chemical properties of fluoride gel to be used for gelatin gel method and freeze-drying gelatin gel method (control group gel and experimental group gel), and the following results were obtained: 1. Physical properties As the results of naked-eye observations, morphological observations through scanning electron microscope and measurements of gelly strength and viscosity, no distinct difference between control and experimental group gel was noted. 2. Chemical properties The qualitative analyses of fluoride ion with ion chromatogram and pH measurement were carried out, and consequently experimental group gel indicated similar values to control group gel. From the foregoing results, it was learned that no significant difference in their physico-chemical properties was clearly confirmed between control and experimental group gel, and it was suggested that similarly to control group gel, experimental group gel would be an effective gel substance as gel media for the formation process of fluorapatite or the reinforcement method of tooth enamel.

Fluorides, Topical↗
PubMed2005

Comparative analysis of protein aggregates by blue native electrophoresis and subsequent sodium dodecyl sulfate-polyacrylamide gel electrophoresis in a three-dimensional geometry gel.

We describe the comparative analysis of protein aggregates by combining blue native electrophoresis and subsequent sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) using a 3-D geometry gel for simultaneous processing of many samples. The first native electrophoresis step, separating the aggregates, is carried out for a series of samples in parallel lanes within a slab gel. This gel is then placed on the top surface of a cylindrical, 3-D geometry gel for the second denaturing electrophoresis step, separating the proteins composing the aggregates. The samples migrate parallel to the vertical axis of the gel cylinder. Data are acquired online by photodetection of laser-induced fluorescence during electrophoresis. For this purpose, the samples are fluorescently labeled within the slab gel after the first separation step. A 3-D geometry gel separates the equivalent of many conventional SDS slab gels represented by vertical layers in the 3-D gel body. In this way, many samples are analyzed in the same gel under identical conditions, improving comparability and resolution and making the process considerably more efficient. This novel technique allowed the identification of several aggregate classes of recombinant proteins expressed in bacteria. We observed that proteins preferentially bind to homolog polypeptides, but also seem to form a trapping mesh co-aggregating with other proteins. The aggregation pattern revealed by this technique supplements data obtained from standard two-dimensional gel electrophoresis analysis. We expect interesting applications, for instance in aggregate monitoring of clinical samples. It should be feasible to quickly gain a diagnostic picture during amyloid-related neurodegenerative disease development or to observe drug effects on protein aggregation.

Bacterial Proteins↗
PubMed1997

Capillary electrophoresis of DNA fragments in 9 to 20% uncrosslinked polyacrylamide gels: unique separating capacity hypothetically related to maintenance of random-coil DNA conformation independently of gel concentration.

DNA fragments (0.1 to 2 kb) were separated by capillary electrophoresis (CE) in 9 to 20% uncrosslinked polyacrylamide gels with a resolving power ranging from 3 to o.1 million theoretical plates/meter across that DNA size range. The unique feature of electrophoresis in 18 to 20% uncrosslinked polyacrylamide is that it provides a method capable of resolving charge isomeric species of DNA fragments (0.4 to 2 kb), confirming a previous report by Heiger et al. [Heiger DN, Cohen AS, Karger BL. J Chromatogr 516 (1990) 33-48]. A similarly unique resolving capacity of uncrosslinked polyacrylamide gels for DNA previously reported is that for heteroduplex DNA [Pulyaeva H, Zakharov SF, Garner MM, Chrambach A. Electrophoresis 15 (1994) 1095-1100] matched by crosslinked gels only in the presence of denaturants [Peeters AV, Kotze MJ. PCR Methods Appl 4 (1994) 188-190; Ganguly A, Rock MJ, Prockop DJ. Proc Natl Acad Sci USA 90 (1993) 10 325-10 329]. A clue as to the cause of that unique resolving capacity of crosslinked polyacrylamide is provided by the finding in the present study of a single, gel concentration independent KR [retardation coefficient, d(log mobility)/d(gel concentration)] for the DNA fragments, which contrasts with the decrease of KR with gel concentration observed for crosslinked polyacrylamide across a wide concentration range [Orban L, Chrambach A. Electrophoresis 12 (1991) 241-246; Tietz D, Chrambach A. Electrophoresis 14 (1993) 185-190]. Since the decrease of KR with gel concentration correlates with a decrease in equivalent molecular radius [Tietz D, Chrambach A. Electrophoresis 14 (1993) 185-190], it has been interpreted as being due to the transition from a random-coiled to a stretched DNA conformation upon passage through gels of increasing concentration. Since in uncrosslinked gels the decrease of KR does not occur, it is correspondingly assumed that the random-coil conformation of DNA is maintained in those gels in the investigated concentration range up to 20%. The maintenance of random-coil conformation [Tietz D, Chrambach A. Electrophoresis 14 (1993) 185-190]. The effect of denaturants in allowing for resolution of heteroduplex DNA in crosslinked gels [Peeters AV, Kotze MJ. PCR Methods Appl 4 (1994) 188-190; Ganguly A, Rock MJ, Prockop DJ, Proc Natl Acad Sci USA 90 (1993) 10 325-10 329] supports that hypothesis of the enhanced resolving power of electrophoresis in gels that maintain random-coiled DNA within the gel concentration range used.

Acrylic Resins↗
PubMed2003

Cumulative irritation comparison of adapalene gel and solution with 2 tazarotene gels and 3 tretinoin formulations.

Forty-two subjects with normal skin were enrolled in a single-center study to assess the cumulative irritancy potential of adapalene (Differin gel 0.1% and Differin solution 0.1%) compared with tazarotene (Tazorac gels 0.05% and 0.1%), tretinoin (Retin-A Micro gel 0.1%, Avita cream 0.025%, and Avita gel 0.025%), and white petrolatum (negative control). All test materials were applied randomly, under occlusion, to sites located on either side of the midline--the mid thoracic area of the subjects' backs. All patches were applied daily, Monday through Friday, to the same sites, unless the degree of reaction to a test product or adhesive necessitated removal (grade 3). Thirty-eight of the 42 subjects (90.5%) completed the study. Thirty-four of those 38 subjects (89.5%) had to discontinue using both tazarotene concentrations due to intolerance. Patch discontinuations for the remaining test materials were as follows: 7 subjects discontinued use of tretinoin microsphere gel 0.1%, 3 discontinued tretinoin cream 0.025%, 1 discontinued tretinoin gel 0.025%, and 1 discontinued adapalene gel 0.1%. None of the subjects discontinued use of the white petrolatum or the adapalene solution 0.1%. Adapalene gel and solution 0.1% were statistically (P<.01) less irritating than both tazarotene gels 0.1% and 0.05%, tretinoin microsphere gel 0.1%, and tretinoin gel 0.025%, and they were not statistically different from tretinoin gel 0.025%.

Adapalene↗
PubMed2006

Efficacy and safety of once-daily metronidazole 1% gel compared with twice-daily azelaic acid 15% gel in the treatment of rosacea.

Rosacea is an inflammatory dermatologic disorder characterized by the presence of facial erythema, visible blood vessels, papules, and pustules. The National Rosacea Society has established a classification system that identifies 4 distinct rosacea subtypes based on clinical presentation: erythematotelangiectatic, papulopustular, phymatous, and ocular. The goal of topical therapy for rosacea is to reduce inflammatory lesion counts; decrease intensity of erythema; and reduce symptoms such as stinging, burning, and pruritus. Metronidazole and azelaic acid are thought to reduce the inflammation associated with rosacea by inhibiting the production of reactive oxygen species produced by neutrophils. Both metronidazole 1% gel and azelaic acid 15% gel recently have been approved for the treatment of rosacea. The current study was conducted to compare the once-daily application of metronidazole 1% gel with twice-daily applications of azelaic acid 15% gel for the treatment of patients with moderate rosacea (N=160). Both treatments showed similar reductions in inflammatory lesion counts (77% for metronidazole 1% gel and 80% for azelaic acid 15% gel) and high success rates in both global severity (53.7% vs 56.4% for metronidazole 1% gel and azelaic acid 15% gel, respectively) and erythema (42.7% vs 42.3% for metronidazole 1% gel and azelaic acid 15% gel, respectively). On average, the efficacy (including reduction in erythema) of the once-daily application of metronidazole 1% gel and twice-daily applications of azelaic acid 15% gel were similar.

Administration, Cutaneous↗
PubMed2003

Chiral stimuli-responsive gels: helicity induction in poly(phenylacetylene) gels bearing a carboxyl group with chiral amines.

Poly(phenylacetylene) gels (gel-1-H and gel-2-H) bearing a carboxy pendant were synthesized either by the copolymerization of (4-carboxyphenyl)acetylene (gel-1-H) with a bis(phenylacetylene) derivative as the cross-linking reagent using a rhodium complex ([Rh(cod)(2)]BF(4): cod = 1,5-cyclooctadiene) as the catalyst or by the cross-linking of poly[(4-carboxyphenyl)acetylene] with diamines (gel-2-H). The obtained gels were found to swell in DMSO and exhibited an induced circular dichroism (ICD) in the long absorption region of the main chain in the presence of optically active amines. These results indicate that a predominantly one-handed helix can be induced in the polymer network of the gels through chiral acid-base interactions. The swelling properties and the Cotton effect intensities of the gels depend on the cross-linking ratio and the chiral amines. Gel-1-Na and gel-2-Na prepared from gel-1-H and gel-2-H, respectively, also significantly swelled in water and showed ICDs characteristic of chiral amino alcohols and free amino acids in water.

Journal Article↗
PubMed2004

A new isoelectric focusing system for fast two-dimensional gel electrophoresis using a low-concentration polyacrylamide gel supported by a loose multifilament string.

A new isoelectric focusing (IEF) system for two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) has been proposed. In this system, a super-soft and tough IEF gel was achieved by casting polyacrylamide gel down to 2.0% T using a loose multifilament string (LMS) of nylon as a gel support. The IEF apparatus for the LMS-gel, fabricated from acrylic boards, had a cooling water chamber, and eliminated the need of electrode solutions by directly connecting the two ends of individual gels to platinum electrodes. The carrier ampholyte-generated pH gradients using the new IEF system was stable over a long duration of time and a wide range of voltages, and the IEF time became shorter using a 2.0% T gel than using a 4.0% T gel. Also, the LMS-gels prepared in different runs exhibited excellent reproducibility. The new IEF system was applied to 2-D PAGE of a chicken skeletal muscle extract, and it was found that the protein loading capacity, protein entry into the LMS-gels, and protein transfer efficiency from the first-dimensional to the second-dimensional gels were significantly improved by using a low-concentration (2.5% T) gel. Also, proteins of high molecular weight of more than 200 kDa were observed in the 2-D maps, and therefore the new IEF system has a very good potential to be applied for fast 2-D PAGE of high molecular-weight proteins.

Journal Article↗
PubMed1991

Estimation of polyacrylamide gel pore size from Ferguson plots of linear DNA fragments. II. Comparison of gels with different crosslinker concentrations, added agarose and added linear polyacrylamide.

The mobilities of various DNA fragments in two normally migrating molecular weight ladders were studied in polyacrylamide gels containing different concentrations of the crosslinker N,N'-methylenebisacrylamide (Bis). The acrylamide concentration ranged from 2.5-10.5%T (w/v); the Bis concentration ranged from 0.5-10%C (w/w), with respect to total acrylamide. Ferguson plots were constructed for each of the DNA fragments in gels of each composition. The Ferguson plots of the different multimers in each molecular weight ladder were nearly parallel in gels containing 0.5-3%C, converged close to a common intercept at zero gel concentration in gels containing 4%C, and crossed at approximately 1.5%T in gels containing 5 and 10%C. If the mobilities observed for the different DNA fragments at zero gel concentration were also extrapolated to zero DNA molecular weight, a common limiting mobility was observed in gels of all crosslinker concentrations. This limiting mobility was approximately equal to the free solution mobility of DNA. The effective pore radius of each gel was estimated from Ferguson plots based on relative mobilities, using the mobility of the smallest DNA fragment in each molecular weight ladder as the reference mobility. The calculated gel pore radii ranged from 142 nm to 19 nm, respectively, for gels containing 4.6%T, 1.5%C, and 10.5%T, 5 or 10%C. These pore radii are an order of magnitude larger than previously accepted values, but are consistent with scanning electron microscope measurements (Rüchel, R., et al., J. Chromatogr. 1978, 42, 77-90).(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylamides↗