Miller-Galante total knee arthroplasty: the importance of material and design on the revision rate

We have reviewed 142 Miller-Galante I (MG I) total knee arthroplasties (TKAs) with a follow-up of 56 months, and compared these with the outcome of 219 Miller-Galante II (MG II) TKAs with a follow-up of 36 months. In the MG II TKAs we found markedly lower revision rates, higher postoperative Hospital for Special Surgery (HSS) scores, less retropatellar pain and better patellar centring without patellar resurfacing. The higher revision rate in MG I TKAs was mainly due to the need to revise the metal-backed patellae.

A transmission imaging spectrograph and microfabricated channel system for DNA analysis

In this paper we present the development of a DNA analysis system using a microfabricated channel device and a novel transmission imaging spectrograph which can be efficiently incorporated into a high throughput genomics facility for both sizing and sequencing of DNA fragments. The device contains 48 channels etched on a glass substrate. The channels are sealed with a flat glass plate which also provides a series of apertures for sample loading and contact with buffer reservoirs. Samples can be easily loaded in volumes up to 640 nL without band broadening because of an efficient electrokinetic stacking at the electrophoresis channel entrance. The system uses a dual laser excitation source and a highly sensitive charge-coupled device (CCD) detector allowing for simultaneous detection of many fluorescent dyes. The sieving matrices for the separation of single-stranded DNA fragments are polymerized in situ in denaturing buffer systems. Examples of separation of single-stranded DNA fragments up to 500 bases in length are shown, including accurate sizing of GeneCalling fragments, and sequencing samples prepared with a reduced amount of dye terminators. An increase in sample throughput has been achieved by color multiplexing.

DNA cycle sequencing of a common restriction fragment of Staphylococcus aureus bacteriophages by capillary electrophoresis using replaceable linear polyacrylamide

The nucleotide sequence of a part of a 4.9 kbp common restriction fragment isolated from Staphylococcus aureus bacteriophage (bacterial virus) 3A has been determined by capillary electrophoresis (CE). The fast separation of sequencing fragments in linear polyacrylamide solution at a temperature of 55 degrees C allowed the reading of more than 650 bases of sequence in 60 min. The single strand (ss)DNA fragments were prepared by cycle sequencing with fluorescently labeled dideoxy-terminators on the cloned bacteriophage DNA template. With respect to analysis speed, sequence read-length, low sample consumption and automation, CE offers a simple, labor-saving and inexpensive procedure for DNA sequencing. Operating the CE columns at elevated temperature proved to be a rapid procedure capable of extending sequence read-length. The resulting sequence of the common restriction fragment can be used for the preparation of specific primers and oligonucleotide hybridization probes for identification of Staphylococcus aureus bacteriophages and/or prophages belonging to the bacteriophage species 3A.

The use of elevated column temperature to extend DNA sequencing read lengths in capillary electrophoresis with replaceable polymer matrices

Capillary electrophoresis with a replaceable linear polyacrylamide matrix operated at elevated column temperatures of 55 degrees and 60 degrees C was used to extend the separation of DNA sequencing fragments to lengths greater than 800 bases. A solid-state heater was employed to provide stable, uniform temperature control over a significant portion of the capillary. The polymer matrix, 3% w/v linear polyacrylamide in a denaturing buffer, was replaced in the capillary after each run. Using dye-labeled primers and Sequenase chemistry on an M13mp18 single-stranded template, four-color separations for the sequencing products were obtained, with read lengths in excess of 800 bases. This paper also briefly discusses the effects of buffer denaturants and capillary temperature on separation speed, resolution, and gel compression.

Rapid DNA sequencing of more than 1000 bases per run by capillary electrophoresis using replaceable linear polyacrylamide solutions

The read length for DNA sequencing using capillary electrophoresis and replaceable linear polyacrylamide (LPA) solutions has been extended to more than 1000 bases with a run time of 80 min. This result was successfully achieved through the combined use of cycle sequencing with dye-labeled primers, improved matrix and separation conditions, and enhanced base-calling software. The influences of LPA molecular weight and concentration on separation were investigated. Additionally, the separation buffer, column temperature, and electric field were adjusted to increase the number of resolvable DNA fragments per run while maintaining an enhanced separation speed. Using low concentrations [2% (w/v)] of high molecular weight LPA polymers (> 5.5 x 10(6) Da), elevated column temperature (50 degrees C) and moderately high field (150 V/cm), rapid sequencing analysis for more than 1000 bases on a model ssM13mp18 template was obtained with 96.8% accuracy.

DNA sequence analysis of Prinker-modified restriction fragments after collection from capillary electrophoresis with replaceable matrices

This paper demonstrates the procedure of sequencing DNA restriction fragments isolated by a recently developed fraction collector after CE separation. In particular, using pBr 322 plasmid as a model system, a double digest was performed with Eco RI and Pst 1 restriction enzymes to produce two fragments of 749 base pairs (bp) and 3612 bp, both with cohesive ends. Prinkers, specific linkers complementary to the cohesive ends, were then ligated to both fragments (increasing the size by 59 bp each). These Prinker-modified fragments were separated by CE and collected. The success of the collection was demonstrated by reinjection of each isolated fraction with laser-induced fluorescence detection, using ethidium bromide as intercalater. The 808 bp isolated fragment was then polymerase chain reaction-amplified with appropriate primers for the Prinker ends, followed by cycle sequencing. Both strands of the fragment were run on an ABI 373, sequencing 427 bases and 450 bases, respectively, with a read accuracy of 99.3%. This approach with Prinker-modified restriction fragment and automated CE fraction collection can be used as a general procedure for sequencing unknown genomic DNA as well as mutated DNA mixtures.

DNA sequencing by capillary electrophoresis using short oligonucleotide primer libraries

Two strategies for DNA sequencing by primer walking using short oligonucleotide primer libraries have been successfully employed along with capillary electrophoresis using replaceable polymer solutions of linear polyacrylamide and fluorescence detection. A 3.5-kb stretch of the single-stranded M13mp18 template was sequenced with T7 PRISM dye-terminator/Sequenase chemistry. An in-house base-calling program offered read lengths of roughly 450 bases with an average of 97.8% accuracy.

Luteinizing hormone/chorionic gonadotropin bioactivity in the common marmoset (Callithrix jacchus) is due to a chorionic gonadotropin molecule with a structure intermediate between human chorionic gonadotropin and human luteinizing hormone

Chorionic gonadotropin (CG), a pregnancy-specific heterodimeric hormone found in primates, is responsible for CL rescue with pregnancy maintenance. Of the primates, the human and baboon gene sequences are the only structures so far determined. In order to study the structure and function of CG in other primates, we have isolated and sequenced the coding regions for the two subunits of marmoset CG (mCG) by the reverse transcription/polymerase chain reaction method. Study of multiple clones confirmed a high degree of homology with the human sequences (88% and 80% for the alpha and beta nucleotide sequences, respectively). Marmoset CG alpha has an extra four amino acids compared to hCG alpha, whereas the mCG beta sequence has a 3-bp deletion that maintains the reading frame and C-terminal amino acid sequence. Most of the differences between hCG beta and mCG beta peptides occur in the C-terminal region, which includes the loss of two of the O-linked glycosylation consensus sequences and the presence of an N-linked glycosylation consensus sequence. When mCG alpha and beta were co-expressed in CHO cells, assembly of biologically active hormone was confirmed by induced steroid secretion by MA10 cells. Partially purified mCG beta was used to raise anti-mCG antibodies. To date, an antibody has been obtained that is capable of detecting recombinant mCG beta, recombinant mCG dimer, and mCG dimer secreted by cultured marmoset trophoblast. Marmoset CG alpha and beta were also detectable at the transcriptional level in cultured trophoblast by in situ hybridization. This suggests that the LH/CG bioactivity reported from marmoset placentae and embryos is due to a molecule with structural features common to hLH (glycosylation pattern) and hCG (CG beta C-terminal structure).

Differential distribution of mRNA for the alpha- and beta-subunits of chorionic gonadotrophin in the implantation stage blastocyst of the marmoset monkey

We studied the expression of mRNA encoding the alpha- and beta-subunits of marmoset chorionic gonadotrophin (mCG) in implantation stage blastocysts and in a trophoblastic cell line derived from such blastocysts. In this investigation in situ hybridization was carried out using digoxygenin-labelled riboprobes to localize the subunit transcripts. The trophoblastic cell line, known to secrete bioactive mCG, was used as a positive control. Marmoset uterine embryos were cultured to hatched blastocysts and following growth on Matrigel or plastic were processed for in situ hybridization at developmental stages ranging from 13-15 days post-conception. In serial sections mCG-beta mRNA was detected mainly in polar trophoblast. The mRNA for mCG-alpha was expressed more uniformly in polar and mural trophoblast. Transcripts for the beta-subunit were not expressed, or present as weak signals, in the inner cell mass (ICM) and endoderm. However, low levels of mRNA for mCG-alpha were detected in the ICM and visceral endoderm. We have concluded that mRNA for mCG-beta was primarily localized to patches of syncytiotrophoblast at the embryonic pole and sparsely distributed in mural trophoblast, while the transcripts for mCG-alpha were distributed more uniformly in differentiating cytotrophoblast and syncytium, and at much lower levels in ICM and early endoderm.

Sequence dependent migration behavior of double-stranded DNA in capillary electrophoresis

Capillary electrophoresis (CE) with a replaceable linear polyacrylamide (LPA) sieving matrix was used to examine sequence-dependent migration of double-stranded DNA fragments. It has been found that DNA conformational effects were significant under high electric field separations, especially using high resolution matrices. Compared to linear DNA-ladder standards, both anomalously slow and rapid DNA fragments were observed, with the degree of anomalous migration depending on the electric field strength, polymer concentration, column temperature, and background electrolyte (denaturants, sodium and magnesium ions, DNA-intercalating dyes). By selecting a combination of electrophoretic conditions (e.g. 3% T LPA, elevated capillary temperature, lower electric field strength and addition of DNA intercalating dyes), molecular weight dependent separations were closely restored.

DNA sequencing by capillary electrophoresis: use of a two-laser-two-window intensified diode array detection system

This paper presents the principles of an instrument designed for DNA sequencing using the standard four-dye-labeled primer approach. The method is based on capillary electrophoresis with laser-induced fluorescence and an intensified diode array detector. An important goal of the instrument design has been a detection system that possesses high sensitivity and high spectral resolution. Based on an analysis of the spectral characteristics of the four standard dye-labeled primers, FAM, JOE, ROX, and TAMRA, the strategy has been to use a two-laser-two-window approach, in which a 488-nm argon ion laser illuminates one window, followed by a 543-nm helium-neon laser illuminating the second window. The two-window approach has no moving parts and permits continuous illumination. Spectral resolution is provided by a grating spectrograph and a cooled intensified diode array. The estimated limit of detection for the standard four dye-labeled primers was found to be in the sample concentration range of 1 x 10(-12) M. To achieve these low levels, complete free-radical polymerization of polyacrylamide has been found to be necessary in order to reduce background noise. In addition, reduction in background noise was accomplished by continual purging of the anodic reservoir in order to prevent electrolysis products from entering the capillary. Separation of DNA sequencing reaction products is demonstrated on a 9% T linear polyacrylamide column.

Separation of DNA fragments by capillary electrophoresis using replaceable linear polyacrylamide matrices

The use of low percent (1.5-6% T) replaceable linear polyacrylamide (LPA) network matrices for rapid separation of double-stranded DNA fragments was explored. Separations of fragments ranging from 20 to 23,000 base pairs were readily achieved. Typically, 4 x 10(6) theoretical plates/m were obtained in less than 30 min. Short separation times under 2 min were also possible, using the DNA intercalating dye, ethidium bromide, along with high electric fields. The high resolving power of linear polyacrylamide was demonstrated in the separation of two fragments which differ by a single base pair (123/124 base pairs) using 6% T LPA and ethidium bromide intercalation. This LPA composition allowed for the possible single base-pair resolution of dsDNA fragments up to 300 base pairs in length. Several concentrations of the linear polyacrylamide for different ranges of fragment lengths have been employed. In addition, replaceable LPA offers the advantage of a fresh separation matrix for each run, thus overcoming column stability problems and minimizing needs for sample cleanup. Electro-osmotic flow was substantially reduced using stable capillary coatings, which were required for obtaining high efficiencies and good reproducibility.

DNA sequencing by capillary electrophoresis with replaceable linear polyacrylamide and laser-induced fluorescence detection

Replaceable linear polyacrylamide (LPA) has been utilized as a sieving matrix for DNA sequencing by capillary electrophoresis (CE). Difficulties associated with cross-linked polyacrylamide gel stability have been overcome for the routine application of CE to DNA sequencing. A simple laser-induced fluorescence (LIF) detection system based on a single laser and two photomultipliers (PMT) has been adopted for this work. Sequencing information for four bases has been obtained from two fluorescent dyes and two peak height ratios, detected in two optical channels. FAM- and JOE-labeled M13 (-21) primers have been chosen because both dyes are efficiently excited with a low-power argon ion laser, can be optically separated, and exhibit minimal dye-based shifts in DNA fragment mobilities. Addition of denaturants to the electrophoresis running buffer (1 x TBE, 3.5 M urea, 30% formamide) and column operation at 32 degrees C permitted the resolution of difficult compressed sites in the sequence of phage M13mp18. Careful examination of the polymerization reaction of LPA has led to methodology that has proven to be reproducible for obtaining DNA sequencing information of M13mp18 phage for 350 nucleotides in close to 30 min.