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C Dennis

Publications and source records attributed to C Dennis.

At least 19 recordsLinked to original sources
PubMed2001

Histone tails modulate nucleosome mobility and regulate ATP-dependent nucleosome sliding by NURF.

Nucleosome Remodeling Factor (NURF) is an ATP-dependent nucleosome remodeling complex that alters chromatin structure by catalyzing nucleosome sliding, thereby exposing DNA sequences previously associated with nucleosomes. We systematically studied how the unstructured N-terminal residues of core histones (the N-terminal histone tails) influence nucleosome sliding. We used bacterially expressed Drosophila histones to reconstitute hybrid nucleosomes lacking one or more histone N-terminal tails. Unexpectedly, we found that removal of the N-terminal tail of histone H2B promoted uncatalyzed nucleosome sliding during native gel electrophoresis. Uncatalyzed nucleosome mobility was enhanced by additional removal of other histone tails but was not affected by hyperacetylation of core histones by p300. In addition, we found that the N-terminal tail of the histone H4 is specifically required for ATP-dependent catalysis of nucleosome sliding by NURF. Alanine scanning mutagenesis demonstrated that H4 residues 16-KRHR-19 are critical for the induction of nucleosome mobility, revealing a histone tail motif that regulates NURF activity. An exchange of histone tails between H4 and H3 impaired NURF-induced sliding of the mutant nucleosome, indicating that the location of the KRHR motif in relation to global nucleosome structure is functionally important. Our results provide functions for the N-terminal histone tails in regulating the mobility of nucleosomes.

Adenosine Triphosphate↗
PubMed2001

The bugs of war.

Explore the source record for details and available documents.

Animals↗
PubMed2001

Primary pulmonary botryomycosis: an important differential diagnosis for lung cancer.

This is the sixteenth reported case of pulmonary botryomycosis, an uncommon suppurative bacterial infection of the lung. We describe the case of a 69-year-old man who presented with a chronic cough and intermittent haemoptysis and on subsequent chest computed tomographic scan imaging was found to have a right lower lobe mass. He underwent a right lower lobectomy for presumed lung cancer. Histological analysis however revealed a bacterial aetiology. The past literature is reviewed outlining the pathogenesis and difficulties of clinical and radiological diagnosis. Primary pulmonary botryomycosis forms an important curative differential diagnosis for lung cancer.

Actinobacillus Infections↗
PubMed2000

Short-term implicit memory: visual, auditory, and cross-modality priming.

Short-term implicit memory was examined for mixed auditory (A) and visual (V) stimuli. In lexical decision, words and nonwords were repeated at lags of 0, 1, 3, and 6 intervening trials, in four prime-target combinations (VV, VA, AV, AA). Same-modality repetition priming showed a lag x lexicality interaction for visual stimuli (nonwords decayed faster), but not for auditory stimuli (longer lasting smooth decay for both words and nonwords). These modality differences suggest that short-term priming has a perceptual locus, with the phonological lexicon maintaining stimuli active longer than the orthographic lexicon and treating pseudowords as potential words. We interpret these differences in terms of the different memory needs of speech recognition and text reading. Weak cross-modality short-term priming was present for words and nonwords, indicating recoding between perceptual forms.

Adult↗
PubMed1998

The electrocardiographic exercise test in a population with reduced workup bias: diagnostic performance, computerized interpretation, and multivariable prediction. Veterans Affairs Cooperative Study in Health Services #016 (QUEXTA) Study Group. Quantitative Exercise Testing and Angiography.

BACKGROUND: Empirical scores, computerized ST-segment measurements, and equations have been proposed as tools for improving the diagnostic performance of the exercise test. OBJECTIVE: To compare the diagnostic utility of these scores, measurements, and equations with that of visual ST-segment measurements in patients with reduced workup bias. DESIGN: Prospective analysis. SETTING: 12 university-affiliated Veterans Affairs Medical Centers. PATIENTS: 814 consecutive patients who presented with angina pectoris and agreed to undergo both exercise testing and coronary angiography. MEASUREMENTS: Digital electrocardiographic recorders and angiographic calipers were used for testing at each site, and test results were sent to core laboratories. RESULTS: Although 25% of patients had previously had testing, workup bias was reduced, as shown by comparison with a pilot study group. This reduction resulted in a sensitivity of 45% and a specificity of 85% for visual analysis. Computerized measurements and visual analysis had similar diagnostic power. Equations incorporating nonelectrocardiographic variables and either visual or computerized ST-segment measurement had similar discrimination and were superior to single ST-segment measurements. These equations correctly classified 5 more patients of every 100 tested (areas under the receiver-operating characteristic curve, 0.80 for equations and 0.68 for visual analysis; P < 0.001) in this population with a 50% prevalence of disease. CONCLUSIONS: Standard exercise tests had lower sensitivity but higher specificity in this population with reduced work-up bias than in previous studies. Computerized ST-segment measurements were similar to visual ST-segment measurements made by cardiologists. Considering more than ST-segment measurements can enhance the diagnostic power of the exercise test.

Adult↗
PubMed1998

Aspergillus infection of the respiratory tract after lung transplantation: chest radiographic and CT findings.

The objective of our study was to assess radiographic and CT findings in lung transplant patients with evidence of Aspergillus colonization or infection of the airways and correlate the findings with clinical, laboratory, bronchoalveolar lavage, biopsy and autopsy findings. The records of 189 patients who had undergone lung transplantation were retrospectively reviewed for evidence of Aspergillus colonization or infection of the airways. Aspergillus was demonstrated by culture or microscopy of sputum or bronchoalveolar lavage fluid or histologically from lung biopsies or postmortem studies in 44 patients (23 %). Notes and radiographs were available for analysis in 30 patients. In 12 of the 30 patients (40 %) chest radiographs remained normal. In 11 of 18 patients with abnormal radiographs pulmonary abnormalities were attributed to invasive pulmonary aspergillosis (IPA) in the absence of other causes for pulmonary abnormalities (8 patients) or because of histological demonstration of IPA (3 patients). In these 11 patients initial radiographic abnormalities were focal areas of patchy consolidation (8 patients), ill-defined pulmonary nodules (2 patients) or a combination of both (1 patient). In some of the lesions cavitation was demonstrated subsequently. At CT a "halo" of decreased density was demonstrated in some of the nodules and lesion morphology and location were shown more precisely. Demonstration of Aspergillus from the respiratory tract after lung transplantation does not necessarily reflect IPA but may represent colonization of the airways or semi-invasive aspergillosis. The findings in patients with IPA did not differ from those described in the literature in other immunocompromised patients, suggesting that surgical disruption of lymphatic drainage and nervous supply or effects of preservation and transport of the transplant lung do not affect the radiographic appearances.

Adult↗
PubMed1998

Can computerization of the exercise test replace the cardiologist?

BACKGROUND: The type of practitioners who use the standard exercise test is changing. Once a tool of the cardiologist, the standard exercise test is now being performed by internists and other noncardiologists. Because this change could be facilitated by computerization similar to the computerized interpretation programs available for the resting electrocardiograph (ECG), we performed this analysis. A secondary aim was to demonstrate the effects of medication status and resting ECG abnormalities on test diagnostic characteristics because these factors affect utility of the exercise test by the generalist. METHODS AND RESULTS: A retrospective analysis was performed of consecutive patients referred at 2 university-affiliated Veteran's Affairs Medical Centers and a Hungarian Hospital for evaluation of chest pain and possible ischemic heart disease. There were 1384 consecutive male patients without a prior myocardial infarction with complete data who had exercise tests and coronary angiography between 1987 and 1997. Measurements included clinical, exercise test data, and visual interpretation of the ECG recordings as well as more than 100 computed measurements from the digitized ECG recordings and compilation of angiographic data from clinical reports. The computer measurements had similar diagnostic power compared with visual interpretation. Computerized measurements from maximal exercise or recovery were equivalent or superior to all other measurements. Prediction equations applied by computer were superior to single ECG measurements. Beta-blockers had no effect on test characteristics, whereas resting ST depression was associated with decreased specificity and increased sensitivity. CONCLUSIONS: Computerized exercise ST measurements are comparable to visual ST measurements by a cardiologist; computerized scores that included clinical and exercise test results exhibited the greatest diagnostic power. Applying scores with a computer allows the practicing physician to improve the diagnostic characteristics of the standard exercise test. This approach is successful even when there is resting ST depression, thus lessening the need for more expensive nuclear or imaging studies.

Adult↗
PubMed1997

Vitronectin expression in differentiating neuroblastic tumors: integrin alpha v beta 5 mediates vitronectin-dependent adhesion of retinoic-acid-differentiated neuroblastoma cells.

The metastatic potential of undifferentiated neuroblastomas is typically lost when differentiation into ganglioneuroblastomas occurs spontaneously or is induced. Cell adhesion may play a role in metastasis, and we have shown recently that expression of integrin alpha v beta 5 protein and mRNA is up-regulated in ganglioneuroblastomas in vivo. To investigate whether interactions of alpha v beta 5 with matrix components play a role in the loss of metastatic potential, we used immunohistochemical and in situ hybridization to analyze neuroblastic tumors at various stages of differentiation for expression of the alpha v beta 5 ligands, vitronectin and osteopontin, and determined the ability of vitronectin to promote attachment and neurite outgrowth in vitro in a retinoic-acid-differentiated neuroblastoma cell model. We found that vitronectin, but not osteopontin, was expressed in 5 of 5 ganglioneuroblastomas but was absent or weakly expressed in 6 of 6 undifferentiated neuroblastomas. Neuronal cell vitronectin was detected in 7 of 9 ganglioneuromas, 5 of 8 peripheral ganglia, and 14 of 21 adrenal gland medullae, confirming expression of vitronectin in mature peripheral neurons. In vitro, vitronectin promoted attachment of both undifferentiated and retinoic-acid-differentiated neuroblastoma cells, which was inhibited 20 and 60%, respectively, by monoclonal antibody anti-integrin alpha v beta 5. Vitronectin-promoted neurite outgrowth of retinoic-acid-differentiated neuroblastoma cells was not inhibited by monoclonal antibody anti-alpha v beta 5. These data suggest that the synthesis of vitronectin and the ability of integrin alpha v beta 5 to mediate vitronectin adhesion on retinoic-acid-differentiated neuroblastoma cells may promote differentiation of neuroblastoma cells in vivo.

Adrenal Gland Neoplasms↗
PubMed1996

Tuberculous pericarditis.

A patient with a 5-month history of pericardial effusion and unsuccessful steroid treatment was found at pericardial exploration to have thickened pericardium adhered to the heart. After anterior pericardiectomy, histologic examination revealed severe granulomatous pericarditis resulting from infection with Mycobacterium tuberculosis. Despite the pericardiectomy and antituberculous therapy, the patient continued to have symptoms, including bilateral pleural effusions, 4 days after discharge from the hospital. After a second exploration (after echocardiography revealed decreased left ventricular function and hemodynamic findings showed persistent constriction), anterior and posterior cardiectomy was deemed necessary. Pleural effusion did not recur, and the patient was discharged with antituberculous drug therapy. This rare extrapulmonary form of tuberculosis can have an insidious or sudden onset, and diagnosis is complicated by false-negative tuberculin tests, nonspecific radiographic and echocardiographic findings, and time-consuming bacteriologic culture. Previous high mortality with the disease has been decreased to approximately 40% by the advent of antituberculous drug therapy. The still significant mortality reflects the difficulty in early diagnosis and the serious effects of pericardial effusion and constriction.

Age Distribution↗
PubMed1996

Measurement of health-related quality of life before and after heart-lung transplantation.

BACKGROUND: The measurement of the quality of the outcome of treatment as viewed by patients is becoming increasingly recognized as an important aspect of decision making in all health services. This major study, which set out to measure the health-related quality of life outcomes of heart and lung transplantation, developed from the experience gained in the United Kingdom and United States studies of the cost and benefits of heart transplantation in the 1980s. METHODS: The design was prospective with a cohort of patients completing a variety of generic and specific health-related quality of life questionnaires at intervals before and after heart and lung transplantation. The sample size was not prescribed; one of the aims of the project was to test the feasibility of introducing routine monitoring of health-related quality of life outcomes as an integral part of a developing transplant service. RESULTS: Before the operation, there was evidence of deterioration over time in all dimensions of the Nottingham Health Profile. In comparing Profile scores at less than 3 months before with those at 3 to 6 months after transplantation, statistically significant improvements were evident (p < 0.001). Mean scores at intervals up to 2 years after transplantation showed little change over time and compared well with those from a general population sample. Hospital Anxiety and Depression Scale scores were reduced significantly (p < 0.01) by 1 year after heart and lung transplantation. In the pretransplantation period, at least 90% of 101 patients had some level of restriction in home and leisure activities, reducing to between 2% and 24% at 1 year after transplantation. Similarly, 79 patients (78%) had chest pain, and 101 (100%) were breathless before transplantation, reducing to 54% and 39%, respectively, at 1 year after surgery; by which time, for 8 of 10 patients, the problem was occasional. CONCLUSIONS: Highly significant improvements were observed in the physical, social, and emotional dimensions of health-related quality of life of patients after heart-lung transplantation. The advantages and feasibility of combining generic and condition-specific questionnaires are shown together with the need to develop new measures with greater sensitivity to the smaller peaks and troughs of recovery.

Activities of Daily Living↗
PubMed1995

Single lung transplantation for end stage emphysema.

BACKGROUND: The first successful single lung transplantation was carried out in 1983 for pulmonary fibrosis. Because of the inherent advantages of single lung transplantation, a transplantation programme has been started for patients with end stage lung disease due to emphysema. METHODS: Between October 1990 and August 1993 25 patients with severe emphysema (15 men, mean age 51 years) received a single lung transplant at our institution. All patients were severely disabled with a mean (SD) 12 minute walking distance of 281 (165) metres. There were five deaths in the series, four in the first 20 days and one on day 503. Two patients suffered graft compression by air trapping in the native lung. Bronchial narrowing requiring insertion of endobronchial stenting occurred in four patients. RESULTS: Mean (SD) FEV1 improved from a preoperative value of 17.8(13%) predicted to a six month value of 53.6(13)%, and FEV1/FVC from 23.8(12)% to 68.6(15)%. After the transplant 12 patients are in New York Heart Association (NYHA) class I and the rest of the survivors are in NYHA II. Actuarial survival was 82% at one year and 74% at three years. CONCLUSIONS: Single lung transplantation is an effective treatment for end stage lung disease due to emphysema and carries an acceptable mortality and morbidity.

Adult↗