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Biomedical subjects

C Abbott

Publications and source records attributed to C Abbott.

At least 19 recordsLinked to original sources
PubMed2005

Apatite/amelogenin coating on titanium promotes osteogenic gene expression.

Osteoblast differentiation and extracellular matrix production are pivotal processes for implant osseointegration or bone tissue engineering. We hypothesized that a biomimetic coating on titanium surfaces, consisting of apatite and amelogenin, would promote such processes. Human Embryonic Palatal Mesenchymal pre-osteoblasts were used as a model for the evaluation of cell adhesion and spreading patterns, as well as mRNA expression of certain osteoblastic gene products. Real-time PCR showed significant (p < 0.05) increase in expression of type I collagen, alkaline phosphatase, and osteocalcin from cells grown on titanium with an apatite/amelogenin composite, as compared with that from cells grown on a pure titanium or apatite coating only. Osteocalcin expression was specifically stimulated by amelogenin added to the culture media. Enhanced attachment and cell spreading were also observed. The biomimetic coating promoting cell adhesion and osteoblast differentiation may have great potential for future dental and biomedical applications.

Alkaline Phosphatase↗
PubMed2002

p53 and bcl-2 immunohistochemistry in preoperative biopsies as predictors of biochemical recurrence after radical prostatectomy.

OBJECTIVE: To evaluate p53 and bcl-2 immunohistochemistry in preoperative biopsies and radical prostatectomy specimens, as predictors of biochemical recurrence. PATIENTS AND METHODS: Preoperative biopsies from 73 men, and the radical prostatectomies from these men and from a further 47 men, were evaluated. The serum prostate specific antigen (PSA) level, Gleason score, pathological stage and margin involvement were recorded. The immunohistochemical expression of p53 and bcl-2 was studied on a representative area of tumour with the highest Gleason grade. The median follow-up was 53 months. RESULTS: During the follow-up 47 of the 120 patients had a biochemical recurrence. Capsular penetration was present in 63 (53%) and the surgical margins were positive in 47 (39%). The Gleason score was < 7 in 81 (68%) patients; p53 was positive in 40 (66%) of 61 biopsies and 84 (71%) of 118 prostatectomy specimens. Bcl-2 was positive in eight (13%) of 63 biopsies and 20 (17%) of 118 prostatectomies. On multivariate analysis the biopsy p53, Gleason score and serum PSA were significant predictors of recurrence. On multivariate analysis, capsular penetration, PSA and margin status at prostatectomy were significant predictors of recurrence. There was also a significant interaction between PSA and margin status. Although univariately significant, neither p53 nor bcl-2 featured in the final multivariate model. CONCLUSION: Biopsy p53 status significantly predicts recurrence after radical prostatectomy, but its low specificity and technical issues suggest that it will not be useful in the clinical setting. However, a patient with negative p53 on biopsy is likely to have a good prognosis on prolonged follow-up.

Aged↗
PubMed2001

Computed tomography versus intravenous urography in diagnosis of acute flank pain from urolithiasis: a randomized study comparing imaging costs and radiation dose.

The equivalent sensitivity of non-contrast computed tomography (NCCT) and intravenous urography (IVU) in the diagnosis of suspected ureteric colic has been established. Approximately 50% of patients with suspected ureteric colic do not have a nephro-urological cause for pain. Because many such patients require further imaging studies, NCCT may obviate the need for these studies and, in so doing, be more cost effective and involve less overall radiation exposure. The present study compares the total imaging cost and radiation dose of NCCT versus IVU in the diagnosis of acute flank pain. Two hundred and twenty-four patients (157 men; mean age 45 years; age range 19-79 years) with suspected renal colic were randomized either to NCCT or IVU. The number of additional diagnostic imaging studies, cost (IVU A$136; CTU A$173), radiation exposure and imaging times were compared. Of 119 (53%) patients with renal obstruction, 105 had no nephro-urological causes of pain. For 21 (20%) of these patients an alternative diagnosis was made at the initial imaging, 10 of which were significant. Of 118 IVU patients, 28 (24%) required 32 additional imaging tests to reach a diagnosis, whereas seven of 106 (6%) NCCT patients required seven additional imaging studies. The average total diagnostic imaging cost for the NCCT group was A$181.94 and A$175.46 for the IVU group (P < 0.43). Mean radiation dose to diagnosis was 5.00 mSv (NCCT) versus 3.50 mSv (IVU) (P < 0.001). Mean imaging time was 30 min (NCCT) versus 75 min (IVU) (P < 0.001). Diagnostic imaging costs were remarkably similar. Although NCCT involves a higher radiation dose than IVU, its advantages of faster diagnosis, the avoidance of additional diagnostic imaging tests and its ability to diagnose other causes makes it the study of choice for acute flank pain at Christchurch Hospital.

Adult↗
PubMed2001

Primary papillary hyperplasia of the gallbladder: a rare cause of biliary colic.

Primary papillary hyperplasia of the gallbladder is a rare, poorly defined, clinicopathologic entity in adults. The authors describe a 12-year-old girl with this finding in the neck and body of the gallbladder. She presented with biliary colic, and ultrasonography of the gallbladder showed persistent thickening of the gallbladder wall but no evidence of calculi. Her symptoms resolved completely after cholecystectomy.

Biliary Tract Diseases↗
PubMed2001

Patient outcomes after peripheral revascularization surgery.

Acquired peripheral vascular disease (PVD) is a significant problem in the United States, resulting in both morbidity and mortality. The purpose of the pilot study was to determine patient outcomes after peripheral revascularization surgery. The specific aims of the pilot study were to examine peripheral revascularization surgical patient outcomes (PVD-related clinical symptoms, functioning, atherosclerotic disease risk factor reduction, and patient satisfaction) and to determine the influence of selected patient demographic characteristics (gender, age) on selected patient outcomes (PVD-related clinical symptoms, functioning, atherosclerotic disease risk factor reduction, and patient satisfaction). A prospective, repeated measures design was used for the study. A total of 39 patients, 18 women and 21 men, participated in the study, with a mean age of 68.86 years (SD = 13.61). The average length of hospitalization after surgery was 4.05 days. At 1 month after discharge, the majority of patients had relief from claudication and paresthesia. In regard to outcomes related to atherosclerotic risk factor modification, patients reported that they exercised on a routine basis, an average of 5.31 +/- 1.97 times per week. Before surgery, 21 patients reported that they smoked; 6 patients reported that they continued to smoke at follow-up. There were no significant differences in mean total scores of atherosclerotic risk modification by either gender or age groups (<65 or > or =65 years) with the use of one-way analyses of variance (ANOVAs). By using a Likert scale (ie, 0 to 10), the mean level of functioning was 8.18 +/- 2.76, with women having significantly higher mean levels of functioning (F = 4.26, P <.05). Comparing baseline scores of functioning on the Medical Outcomes Study Short-Form 36 (MOS SF-36), there was a significant improvement (F = 2.11, P <.05) in general health subscale scores at 1 month after surgery. Subjects' mean overall satisfaction with the results of surgery, with a 0 to 10 scale, was 7.33 +/- 2.84. Again, by using one-way ANOVAs, females had significantly higher mean satisfaction rating than males (F = 4.52, P <.05). Although findings from this pilot study are limited in their generalizability, clinicians need to continue to evaluate opportunities to further reduce variability in clinical practice patterns for optimal patient outcomes. Study findings also indicated that additional interventions are warranted to educate and provide rehabilitation for patients regarding an exercise program and overall behavior modification strategies to reduce risk for atherosclerotic disease.

Aged↗
PubMed2001

The 2000 Canadian recommendations for the management of hypertension: part two--diagnosis and assessment of people with high blood pressure.

OBJECTIVE: To provide updated, evidence-based recommendations for the diagnosis and assessment of high blood pressure in adults. OPTIONS: For people with high blood pressure, the assignment of a diagnosis of hypertension depends on the appropriate measurement of blood pressure, the level of the blood pressure elevation, the duration of follow-up and the presence of concomitant vascular risk factors, target organ damage and established atherosclerotic diseases. For people diagnosed with hypertension, defining the overall risk of adverse cardiovascular outcomes requires laboratory testing, a search for target organ damage and an assessment of the modifiable causes of hypertension. Out-of-clinic blood pressure assessment and echocardiography are options for selected patients. OUTCOMES: People at increased risk of adverse cardiovascular outcomes and were identified and quantified. EVIDENCE: Medline searches were conducted from the period of the last revision of the Canadian recommendations for the management of hypertension (May 1998 to October 2000). Reference lists were scanned, experts were polled, and the personal files of the subgroup members and authors were used to identify other studies. All relevant articles were reviewed and appraised, using prespecified levels of evidence, by content experts and methodological experts. VALUES: A high value was placed on the identification of people at increased risk of cardiovascular morbidity and mortality. BENEFITS, HARMS AND COSTS: The identification of people at higher risk of cardiovascular disease will permit counselling for lifestyle manoeuvres and the introduction of antihypertensive drugs to reduce blood pressure for patients with sustained hypertension. In certain settings, and for specific classes of drugs, blood pressure lowering has been associated with reduced cardiovascular morbidity and/or mortality. RECOMMENDATIONS: The present document contains detailed recommendations pertaining to aspects of the diagnosis and assessment of patients with hypertension, including the accurate measurement of blood pressure, criteria for the diagnosis of hypertension and recommendations for follow-up, routine and optional laboratory testing, assessment for renovascular hypertension, home and ambulatory blood pressure monitoring, and the role of echocardiography in hypertension. VALIDATION: All recommendations were graded according to strength of the evidence and voted on by the Canadian Hypertension Recommendations Working Group. Only the recommendations achieving high levels of consensus are reported here. These guidelines will be updated annually. ENDORSEMENT: These recommendations are endorsed by the Canadian Hypertension Society, The Canadian Coalition for High Blood Pressure Prevention and Control, The College of Family Physicians of Canada, The Heart and Stroke Foundation of Canada, The Adult Disease Division and Bureau of Cardio-Respiratory Diseases and Diabetes at the Centre for Chronic Disease Prevention and Control of Health Canada.

Adrenal Gland Neoplasms↗
PubMed2000

Mutations in Sox18 underlie cardiovascular and hair follicle defects in ragged mice.

Analysis of classical mouse mutations has been useful in the identification and study of many genes. We previously mapped Sox18, encoding an SRY-related transcription factor, to distal mouse chromosome 2. This region contains a known mouse mutation, ragged (Ra), that affects the coat and vasculature. Here we have directly evaluated Sox18 as a candidate for Ra. We found that Sox18 is expressed in the developing vascular endothelium and hair follicles in mouse embryos. Furthermore, we found no recombination between Sox18 and Ra in an interspecific backcross segregating for the Ra phenotype. We found point mutations in Sox18 in two different Ra alleles that result in missense translation and premature truncation of the encoded protein. Fusion proteins containing these mutations lack the ability to activate transcription relative to wild-type controls in an in vitro assay. Our observations implicate mutations in Sox18 as the underlying cause of the Ra phenotype, and identify Sox18 as a critical gene for cardiovascular and hair follicle formation.

Alleles↗
PubMed2000

Low cholesterol and noncardiovascular mortality.

Recent clinical trial data have suggested that low cholesterol might cause increased mortality from noncardiovascular conditions. Several randomized trials have suggested an increase in noncoronary deaths at low levels of total cholesterol. When subcategories for causes of death were investigated, it was noted that hemorrhagic stroke risk was inversely related to total cholesterol, whereas nonhemorrhagic stroke risk was positively related to total cholesterol. Certain cancers were shown to be more common at low total cholesterol levels, namely lung, liver, lymphatic, and hematopoietic cancer. Another issue to consider is whether increased mortality rates are seen in individuals with "naturally" occurring low cholesterol or whether they are seen in individuals whose cholesterol has been deliberately lowered through dietary or drug intervention, or in both. If an association between low cholesterol and noncardiovascular mortality is present, there is continuing uncertainty regarding the mechanism by which it occurs.

Causality↗
PubMed1999

Genomic structure and chromosomal mapping of the murine and human Mbd1, Mbd2, Mbd3, and Mbd4 genes.

DNA methylation is essential for murine development and is implicated in the control of gene expression. MeCP2, MBD1, MBD2, MBD3, and MBD4 comprise a family of mammalian, nuclear proteins related by the presence in each of an amino acid motif called the methyl-CpG binding domain (MBD). Each of these proteins, with the exception of MBD3, is capable of binding specifically to methylated DNA. MeCP2, MBD1 and MBD2 can also repress transcription. We describe the genomic structure and chromosomal localization of the human and murine Mbd1, Mbd2, Mbd3, and Mbd4 genes. We find that the highly similar MBD2 and MBD3 proteins are encoded by genes that map to different chromosomes in humans and mice but show a similar genomic structure. The Mbd1 and Mbd2 genes, in contrast, map together to murine and human Chromosomes (Chrs)18. The Mbd3 and Mbd4 genes map to murine Chrs 10 and 6, respectively, while the human MBD3 and MBD4 genes map to Chrs 19 and 3, respectively.

Animals↗
PubMed1997

The reticulocalbin gene maps to the WAGR region in human and to the Small eye Harwell deletion in mouse.

We describe the localization of the gene encoding reticulocalbin, a Ca2+-binding protein of the endoplasmic reticulum, on human chromosome 11p13 midway between the WT1 and the PAX6 genes and show that it is hemizygously deleted in WAGR individuals. The mouse reticulocalbin gene is also shown to map to the region of conserved synteny on mouse chromosome 2 and to be deleted in the Small eye Harwell (SeyH) mutation. Loss of the reticulocalbin gene could contribute to the early lethality of SeyH and SeyDey homozygotes.

Abnormalities, Multiple↗
PubMed1995

Authentic standards for the reductive-cleavage method. The positional isomers of partially methylated and acetylated or benzoylated 1,5-anhydro-D-galactitol.

Described herein is an efficient method for the synthesis of the sixteen positional isomers of methylated and acetylated or benzoylated 1,5-anhydro-D-galactitol. The compounds are generated simultaneously by partial methylation of 1,5-anhydro-D-galactitol and subsequent benzoylation, and the individual isomers are obtained in pure form by high-performance liquid chromatography. Debenzoylation and acetylation yielded the desired acetates. Reported herein are the 1H NMR spectra of the benzoates and the electron-ionization mass spectra of the acetates and the tetra-O-methyl derivative. Also reported for the acetates and the tetra-O-methyl derivative are their linear temperature-programmed gas-liquid chromatography retention indices on three different capillary columns.

Acetylation↗