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T Dailey

Publications and source records attributed to T Dailey.

9 recordsLinked to original sources
PubMed1996

Reduction in signal overlap results in increased FISH efficiency: implications for preimplantation genetic diagnosis.

BACKGROUND: In the absence of mosaicism, one of the problems of preimplantation genetic diagnosis with FISH is the occurrence of false-negative hybridization results. It has been hypothesized that missing signals are produced by spatial overlap of signals. METHODS AND RESULTS: To investigate the relation among cell density, signal overlap, and hybridization signal detection, 371 blastomeres and 4556 lymphocytes were fixed in different cellular concentrations and analyzed by FISH using probes for chromosomes X, Y, and 18, and their nuclear diameters and FISH results scored. The results showed that the lower the diameter of fixed nuclei, the higher the number of signal overlaps and missing signals. The minimum number of missing signals was obtained when lymphocyte and blastomere nuclei had 40 or more microns in diameter after fixation and FISH. Since blastomeres were fixed individually, results with blastomeres were invariably better than with lymphocytes.

Aneuploidy↗
PubMed1996

Association between nondisjunction and maternal age in meiosis-II human oocytes.

The relationship between advanced maternal age and increased risk of trisomic offspring is well known clinically but not clearly understood at the level of the oocyte. A total of 383 oocytes that failed fertilization from 107 patients undergoing in vitro fertilization were analyzed by FISH using X-, 18-, and 13/21-chromosome probes simultaneously. The corresponding polar bodies were also analyzed in 188 of these oocytes. The chromosomes in the oocyte and first polar body complement each other and provide an internal control to differentiate between aneuploidy and technical errors. Two mechanisms of nondisjunction were determined. First, nondisjunction of bivalent chromosomes resulting in two univalents going to the same pole and, second, nondisjunction by premature chromatid separation (predivision) of univalent chromosomes producing either a balanced (2 + 2) or unbalanced (3 + 1) distribution of chromatids into the first polar body and M-II oocytes. Balanced predivision of chromatids, previously proposed as a major mechanism of aneuploidy, was found to increase significantly with time in culture (P < .005), which suggests that this phenomenon should be interpreted carefully. Unbalanced predivision and classical nondisjunction were unaffected by oocyte aging. In comparing oocytes from women <35 years of age with oocytes from women > or = 40 years of age, a significant increase (P < .001) in nondisjunction of full dyads was found in the oocytes with analyzable polar bodies and no FISH errors. Premature predivision of chromatids was also found to cause nondisjunction, but it did not increase with maternal age.

Adult↗
PubMed1995

The use of first polar bodies for preimplantation diagnosis of aneuploidy.

A large proportion of patients undergoing in-vitro fertilization (IVF) are aged > or = 35 years. It has been estimated that in this age group, 50% of embryos are chromosomally abnormal, with aneuploidy being the major contributing factor. Since the origin of most aneuploidies is maternal meiosis I non-disjunction, unfertilized oocytes could be safely screened for aneuploidy by analysing their first polar bodies. To determine the feasibility of first polar body aneuploidy analysis, polar bodies were analyzed by fluorescence in-situ hybridization (FISH) using probes simultaneously for chromosomes X, Y, 18, 13/21 or X, Y, 18 and 16. Within 6 h of retrieval, 88% showed a normal segregation involving a single chromosome of each kind, with double-dotted hybridization signals, corresponding to dyads (chromosomes in metaphase I composed of two chromatids). The rest showed non-disjunction of full dyads (6%), or an unbalanced pre-division of dyads (6%), which gives a segregation of one chromatid or one dyad and a chromatid with the first polar body. But only 34% of polar bodies analysed 24 h after retrieval or later showed a normal segregation, with most of the other polar bodies showing balanced pre-division, with two separated hybridization signals for all the chromosomes analysed. The rates of non-disjunction and unbalanced pre-division after > or = 24 h in culture were similar to the rates in fresh oocytes. When both types of aneuploidy were considered together, an increase of aneuploidy with maternal age was detected, which although slight, was significant (P = 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Nucleotide sequence of the leukotoxin gene from Actinobacillus actinomycetemcomitans: homology to the alpha-hemolysin/leukotoxin gene family.

The leukotoxin produced by Actinobacillus actinomycetemcomitans has been implicated in the etiology of localized juvenile periodontitis. To initiate a genetic analysis into the role of this protein in disease, we have cloned its gene, lktA. We now present the complete nucleotide sequence of the lktA gene from A. actinomycetemcomitans. When the deduced amino acid sequence of the leukotoxin protein was compared with those of other proteins, it was found to be homologous to the leukotoxin from Pasteurella haemolytica and to the alpha-hemolysins from Escherichia coli and Actinobacillus pleuropneumoniae. Each alignment showed at least 42% identity. As in the other organisms, the lktA gene of A. actinomycetemcomitans was linked to another gene, lktC, which is thought to be involved in the activation of the leukotoxin. The predicted LktC protein was related to the leukotoxin/hemolysin C proteins from the other bacteria, since they shared a minimum of 49% amino acid identity. Surprisingly, although actinobacillus species are more closely related to pasteurellae than to members of the family Enterobacteriaciae, LktA and LktC from A. actinomycetemcomitans shared significantly greater sequence identity with the E. coli alpha-hemolysin proteins than with the P. haemolytica leukotoxin proteins. Despite the overall homology to the other leukotoxin/hemolysin proteins, the LktA protein from A. actinomycetemcomitans has several unique properties. Most strikingly, it is a very basic protein with a calculated pI of 9.7; the other toxins have estimated pIs around 6.2. The unusual features of the A. actinomycetemcomitans protein are discussed in light of the different species and target-cell specificities of the hemolysins and the leukotoxins.

Actinobacillus↗
PubMed1989

Including the poor: the fiscal impacts of Medicaid expansion.

This article presents the fiscal impacts of the comprehensive reform of the Medicaid program put forth by the Health Policy Agenda for the American People. Proposed reforms include establishment of improved uniform eligibility standards, improvement in the scope and depth of coverage in state Medicaid programs, and increased provider payment rates. We estimate that expanding Medicaid coverage to all currently uninsured nonelderly persons below the federal poverty line would cost approximately $9 billion. A substantial portion of these costs would offset current spending elsewhere in the health care system. Improvement of state packages and increased provider payment could result in sharp increases in costs. We provide a range of estimates considering both the set of benefits provided and the behavior of the private insurance market.

Costs and Cost Analysis↗
PubMed1989

Cloning and expression of the leukotoxin gene from Actinobacillus actinomycetemcomitans.

The leukotoxin produced by Actinobacillus actinomycetemcomitans has been implicated in the etiology of juvenile periodontitis. To initiate a genetic analysis of the role of this protein in disease, we have cloned the leukotoxin gene in Escherichia coli. Recombinant colonies carrying toxin gene sequences were isolated by screening a genomic A. actinomycetemcomitans library with a DNA probe for the leukotoxin gene from a related bacterium, Pasteurella haemolytica. To demonstrate that the cloned A. actinomycetemcomitans DNA contained a functional leukotoxin gene, protein extracts of E. coli containing the A. actinomycetemcomitans clone were tested directly for leukotoxic activity against human cell lines in chromium release assays. A construct containing the entire cloned region produced a functional toxin. No cytotoxicity was seen when extracts from cells containing plasmids with deletions in the putative coding region were used. Furthermore, the toxin produced by the cloned gene has the same target cell specificity as the leukotoxin extracted directly from A. actinomycetemcomitans. These results indicate that sequences encoding a functional leukotoxin have been cloned and are expressed in E. coli. Southern blot analysis of DNA from leukotoxin-producing (Lkt+) and non-leukotoxin-producing (Lkt-) strains indicated that the Lkt- strain also contained a copy of the gene.

Actinobacillus↗
PubMed1984

The use of water-soluble contrast enemas in the diagnosis of acute lower left quadrant peritonitis.

The traditional work-up of patients with lower left quadrant peritonitis often includes the eventual use of barium-enema radiography. Diagnosis is usually delayed until adequate patient stabilization allows diagnostic contrast enemas. Delay of accurate diagnosis may, at times, have serious clinical sequelae. The use of barium enema in acute lower left quadrant peritonitis has both theoretic and actual disadvantages. These include extravasation of barium, with resultant barium cellulitis and peritonitis, precipitation of acute obstruction, and delay in evaluation by endoscopy, sonography, computerized tomography, and angiography. Forty recent cases of lower left quadrant peritonitis were evaluated on admission by water-soluble contrast enema. Water-soluble contrast enemas appear to be safe and accurate and avoid the aforementioned disadvantages of barium.

Acute Disease↗
PubMedDate not supplied

No need for pain.

In an attempt to promote as pain free an experience as possible for patients and to improve how pain is managed in all settings, this 500-bed teaching hospital embarked on a hospital-wide quality improvement (QI) initiative. Initial measurement of clinicians' knowledge and attitudes related to pain and surveys on patient satisfaction identified improvement opportunities. Highlights of these findings and the major interventions taken are described. Education of all clinical staff on the major principles of pain management became the primary focus. Major outcomes realized to date have been: (a) a significant increase (p = .01) in physicians and nurses discussing with their patients the importance of managing their pain, (b) development of processes for documenting pain as the fifth vital sign, and (c) a 26% decrease in the use of meperidine. The next steps will be comprehensive monitoring of the effectiveness of pain management by clinical service, increased patient and family education on pain, and development of a formalized pain management competency program for clinical staff.

Benchmarking↗