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James Park

Publications and source records attributed to James Park.

9 recordsLinked to original sources
PubMed2006

Colon pathology detected after a positive screening flexible sigmoidoscopy: a prospective study in an ethnically diverse cohort.

OBJECTIVES: Although the association between distal neoplasia on sigmoidoscopy and proximal colonic pathology on follow-up colonoscopy has been well-described, it is not known if these findings are consistent across ethnic groups. The aim of this study was to evaluate ethnic variations in the prevalence of proximal neoplasia on follow-up colonoscopy after a neoplastic lesion is found on sigmoidoscopy. METHODS: Consecutive asymptomatic patients at average-risk for colorectal cancer who were referred for screening flexible sigmoidoscopy were prospectively enrolled. Colonoscopy was recommended for all patients with a polyp on flexible sigmoidoscopy, regardless of size. Advanced neoplasms were defined as adenomas > or = 10 mm in diameter or any adenoma, regardless of size, with villous histology, high-grade dysplasia, or cancer. RESULTS: Among the 2,207 patients who had sigmoidoscopy, 970 were Caucasian, 765 were African American, 395 were Hispanic, and 77 were Asian. The prevalence of neoplasia in the distal colon was 12.6% in Caucasians, 11.2% in African Americans, 15.9% in Hispanics, and 24.7% in Asians (p = 0.002). Of the 290 patients with neoplastic lesions on sigmoidoscopy, follow-up colonoscopy identified neoplasms in the proximal colon in 63.9% of Caucasians, 59.3% of African Americans, 66.7% of Hispanics, and 26.3% of Asians (p = 0.01). Advanced neoplasms in the proximal colon were highest in African Americans (34.9%) and lowest in Asians (10.5%). CONCLUSIONS: In our study population, Asians demonstrated a higher prevalence of distal colonic neoplasia and a lower prevalence of proximal colonic neoplasia compared to non-Asians. Future studies should explore ethnic variation in colonic neoplasia prevalence and location since ethnic variation could lead to tailored colorectal cancer screening strategies.

Aged↗
PubMed2005

Susceptibility to hepatitis A in patients with chronic liver disease due to hepatitis C virus infection: missed opportunities for vaccination.

Hepatitis A virus (HAV) superinfection is associated with a high risk of liver failure and death in patients with underlying chronic liver disease. Although HAV vaccination is recommended for all patients with chronic hepatitis C virus (HCV) infection, little is known about adherence to these recommendations in clinical practice. The aims of this study were to determine the frequency of HAV testing and vaccination among patients with chronic HCV infection. We conducted a retrospective cohort study of 1,193 patients diagnosed with chronic HCV infection over a 1-year period. During 1,646 person-years of follow-up, patients were seen by their primary care provider a median of 10.0 times (interquartile range, 4.0-20.0). HAV antibody testing was performed in 640 subjects (53.6%), and 317 (49.5%) of those tested were susceptible (HAV antibody negative). Only 94 of the 1,193 patients (7.9%) received the HAV vaccine, including 26.8% of the 317 susceptible patients, 0.9% of the 323 patients who were already immune to HAV, and 1.1% of the 553 subjects who were never tested. Among the 94 vaccinated patients, 45 received only one dose of the vaccine. Three of the unvaccinated patients developed acute HAV infection during follow-up, and 1 of them died of acute liver failure. In conclusion, despite published recommendations to vaccinate against HAV in patients with chronic HCV infection, we found that HAV testing and vaccination rates were low in clinical practice. Public health programs to increase awareness about HAV vaccination in patients with chronic liver disease are needed.

Aged↗
PubMed2004

Acute pancreatitis associated with interferon and ribavirin therapy in patients with chronic hepatitis C.

Acute pancreatitis is a rare complication of interferon (IFN) and ribavirin (RBV) therapy. The aim of this study was to determine the incidence, clinical presentation, and outcome of acute pancreatitis in patients with chronic hepatitis C virus (HCV) infection treated with IFN and RBV combination therapy. We conducted a retrospective review of 1706 HCV-infected patients treated with IFN alpha-2b and RBV. The diagnosis of drug-induced acute pancreatitis was made based on the presence of epigastric pain, elevated amylase and lipase levels, and the absence of other identifiable causes of pancreatitis. Acute pancreatitis was diagnosed in 7 of 1706 HCV-infected patients (0.4%; 95% CI, 0.2 to 0.8%) who were treated with IFN alpha-2b and RBV. The mean age of the patients (four males and three females) was 51.4 +/- 4.7 years and the median duration of therapy prior to development of pancreatitis was 12.0 weeks (range, 4.0-21.0 weeks). All patients presented with epigastric pain associated with nausea, vomiting, and/or fever. The median amylase and lipase values at the time of diagnosis of pancreatitis were 330.0 U/L (range, 182.0-1813.0 U/L) and 500.0 U/L (range, 171.0-2778.0 U/L), respectively. IFN and RBV were discontinued in all patients at the time of diagnosis and six of the seven patients were hospitalized; one patient refused hospital admission. Pancreatitis resolved in all seven patients and none of these individuals had recurrent pancreatitis during a median follow-up of 18.0 months (range, 3.0-27.0 months). In conclusion, IFN and RBV combination therapy is a potential cause of drug-induced pancreatitis in patients with chronic HCV. In these individuals, pancreatitis is often severe enough to warrant hospital admission, although symptoms resolve promptly after discontinuation of antiviral therapy.

Acute Disease↗
PubMed2004

Walking the tightrope: developing an attachment-based/relational curriculum for trainee psychotherapists.

I describe how the Centre for Attachment-based Psychoanalytic Psychotherapy (CAPP) in London has gone about developing an attachment-based/relational curriculum for training psychotherapists. A key problem the training is meant to address is how to maintain a balance between enabling students to absorb research and clinical knowledge of psychological processes at the same time as they learn to maintain the flexibility necessary to address the uniqueness of each individual encounter in the consulting room. I describe the task of the training in terms of a linguistic metaphor: the training needs to ensure that students are theoretically multi-lingual while developing higher levels of fluency in the language of attachment-based/relational psychotherapy. In the pursuit of this approach, my colleagues and I developed a set of ten key propositions - the spine of the relational world - which we felt encapsulated the main theoretical assumptions of attachment-based practice that students need to understand and explore. This has been used to evolve a spiral curriculum, designed to help students engage constructively with the often confusing emotional aspects of clinical work, and with the multiplicity of clinical viewpoints that characterises contemporary psychoanalytic psychotherapy.

Curriculum↗
PubMed2003

Receiver operating characteristic analysis: a general tool for DNA array data filtration and performance estimation.

A critical step for DNA array analysis is data filtration, which can reduce thousands of detected signals to limited sets of genes. Commonly accepted rules for such filtration are still absent. We present a rational approach, based on thresholding of intensities with cutoff levels that are estimated by receiver operating characteristic (ROC) analysis. The technique compares test results with known distributions of positive and negative signals. We apply the method to Atlas cDNA arrays, GeneFilters, and Affymetrix GeneChip. ROC analysis demonstrates similarities in the distribution of false and true positive data for these different systems. We illustrate the estimation of an optimal cutoff level for intensity-based filtration, providing the highest ratio of true to false signals. For GeneChip arrays, we derived filtration thresholds consistent with the reported data based on replicate hybridizations. Intensity-based filtration optimized with ROC combined with other types of filtration (for example, based on significances of differences and/or ratios), should improve DNA array analysis. ROC methodology is also demonstrated for comparison of the performance of different types of arrays, imagers, and analysis software.

Data Interpretation, Statistical↗
PubMed2002

Increasing plasmalogen levels protects human endothelial cells during hypoxia.

Supplementation of cultured human pulmonary arterial endothelial cells (PAEC) with sn-1-O-hexadecylglycerol (HG) resulted in an approximately twofold increase in cellular levels of plasmalogens, a subclass of phospholipids known to have antioxidant properties; this was due, primarily, to a fourfold increase in the choline plasmalogens. Exposure of unsupplemented human PAEC to hypoxia (PO(2) = 20-25 mmHg) caused an increase in cellular reactive oxygen species (ROS) over a period of 5 days with a coincident decrease in viability. In contrast, HG-supplemented cells survived for at least 2 wk under these conditions with no evidence of increased ROS. Hypoxia resulted in a selective increase in the turnover of the plasmalogen plasmenylethanolamine. Human PAEC with elevated plasmalogen levels were also more resistant to H(2)O(2), hyperoxia, and the superoxide generator plumbagin. This protection was seemingly specific to cellular stresses in which significant ROS were generated because the sensitivity to lethal heat shock or glucose deprivation was not altered in HG-treated human PAEC. HG, by itself, was not sufficient for protection; HG supplementation of bovine PAEC had no effect upon plasmalogen levels and did not rescue these cells from the cytotoxic effects of hypoxia. This is the initial demonstration that plasmalogen content can be substantially enhanced in a normal cell. These data also demonstrate that HG can protect cells during hypoxia and other ROS-mediated stress, likely due to the resulting increase in these antioxidant phospholipids.

Animals↗
PubMed1996

Phylogenetic analyses of the homologous transmembrane channel-forming proteins of the F0F1-ATPases of bacteria, chloroplasts and mitochondria.

Sequences of the three integral membrane subunits (subunits a, b and c) of the F0 sector of the proton-translocating F-type (F0F1-) ATPases of bacteria, chloroplasts and mitochondria have been analysed. All homologous-sequenced proteins of these subunits, comprising three distinct families, have been identified by database searches, and the homologous protein sequences have been aligned and analysed for phylogenetic relatedness. The results serve to define the relationships of the members of each of these three families of proteins, to identify regions of relative conservation, and to define relative rates of evolutionary divergence. Of these three subunits, c-subunits exhibited the slowest rate of evolutionary divergence, b-subunits exhibited the most rapid rate of evolutionary divergence, and a-subunits exhibited an intermediate rate of evolutionary divergence. The results allow definition of the relative times of occurrence of specific events during evolutionary history, such as the intragenic duplication event that gave rise to large c-subunits in eukaryotic vacuolar-type ATPases after eukaryotes diverged from archaea, and the extragenic duplication of F-type ATPase b-subunits that occurred in blue-green bacteria before the advent of chloroplasts. The results generally show that the three F0 subunits evolved as a unit from a primordial set of genes without appreciable horizontal transmission of the encoding genetic information although a few possible exceptions were noted.

Amino Acid Sequence↗
PubMedDate not supplied

Use of flexible sigmoidoscopy to screen for colorectal cancer in HIV-infected patients 50 years of age and older.

BACKGROUND: Although many patients with human immunodeficiency virus (HIV) infection are now living well beyond 50 years of age, there are no data available on colorectal cancer screening in this population. The aim of this study was to determine the utility of screening flexible sigmoidoscopy in patients with HIV. METHODS: Consecutive patients at average risk for colorectal cancer who were referred for screening flexible sigmoidoscopy were prospectively identified. A detailed medical history was obtained from all patients before flexible sigmoidoscopy, and colonoscopy was recommended for all subjects with positive sigmoidoscopic findings. RESULTS: A total of 2382 patients were enrolled in the study; 165 were HIV positive. The prevalence of neoplastic lesions (adenomas or adenocarcinomas) in the distal colon was significantly higher in HIV-infected patients than in control subjects (25.5% vs 13.1%, P<.001), and the odds of HIV-infected patients having a neoplastic lesion was significantly higher even after adjustment for potential confounding variables (odds ratio, 2.34; 95% confidence interval, 1.60-3.44). The prevalence of adenomas of any size (25.5% vs 12.9%, P<.001) and advanced neoplasia (7.3% vs 3.8%, P = .03) in the distal colon was significantly higher in HIV-infected patients. Among individuals with positive results on flexible sigmoidoscopy, proximal colonic neoplastic lesions on follow-up colonoscopy were more common in HIV-infected patients after adjustment for age, sex, and race/ethnicity (odds ratio, 1.88; 95% confidence interval, 1.02-3.46). CONCLUSIONS: Patients infected with HIV are more likely to have colonic neoplasms on screening flexible sigmoidoscopy than those without HIV, and these individuals should be offered colorectal cancer screening.

Adenocarcinoma↗