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Biomedical subjects

D Kelly

Publications and source records attributed to D Kelly.

At least 55 records · Page 3Linked to original sources

Cardiac pacemakers and implantable cardioverter defibrillators are unaffected by operation of an extremity MR imaging system.

OBJECTIVE: The objective of our investigation was to determine whether an MR imaging system designed to obtain images of the extremities affects the safety and functionality of pacemakers or that of implantable cardioverter defibrillators (ICDs). MATERIALS AND METHODS: Ex vivo experiments were conducted in which seven pacemakers and seven ICDs were exposed to a 0.2-T extremity MR imaging system. Magnetic field attraction was assessed at three positions relative to the MR imaging system. In addition, the devices were placed into a test apparatus that was oriented parallel and perpendicular relative to the MR imaging system while imaging was performed on a phantom using T1-weighted spin-echo and gradient-echo sequences. Various functional aspects of the pacemakers and ICDs were evaluated before, during (pacemakers only), and after MR imaging. RESULTS: Magnetic field attraction was relatively minor for all devices. The quality of the MR images was unaffected by the devices. Operation of this MR system did not alter any of the functional aspects of the pacemakers or ICDs evaluated in this study. CONCLUSION: According to these data and in consideration of how patients are positioned during examinations--that is, positioned so that the thorax (where the pacemaker or ICD and the corresponding leads are located) does not enter the magnet bore--the results suggest that it should be safe to perform MR imaging in patients with the pacemakers and ICDs evaluated in this study.

Arm↗

Post-traumatic stress responses following liver transplantation in older children.

Eighteen children aged between 7 and 16 years who had undergone a liver transplantation were interviewed using the Child Post-Traumatic Stress Reaction Index (CPTS-RI) to discover if they had post-traumatic stress symptoms. A case control design was used to define which factors were important for the development of post-traumatic stress. Results of a one-way analysis of variance (ANOVA), with post-traumatic stress symptom intensity as measured on the CPTS-RI as the dependent variable, revealed a significant difference between the liver transplantation group compared with children who had a chronic life-threatening illness or had undergone a routine surgical operation. A post hoc (Tukey's HSD test) statistical analysis was performed and significance at the .05 level was found between the liver transplantation group and both the chronic illness group and the routine surgical operation group. Our results indicate that the acute life-threat involved in the liver transplantation contributed to the development of post-traumatic stress. It was thought that dissociation may be important in preventing the resolution of the trauma. Additional investigations are needed with larger numbers in a longitudinal study beginning before the transplant to determine the course of the PTSD symptoms and the appropriate timing of interventions to reduce the harmful effects of these symptoms.

Adolescent↗

Performance of a semiautomated Papanicolaou smear screening system: results of a population-based study conducted in Guanacaste, Costa Rica.

BACKGROUND: Automated cytology devices have utility in quality assurance applications, but the effectiveness of these devices in primary screening is unknown. METHODS: Enrollment smears obtained from 7323 women participating in a population-based study sponsored by the National Cancer Institute were screened manually in Costa Rica and then evaluated independently in the U.S. with the PAPNET system (Neuromedical Systems, Inc., Suffern, NY), a semiautomated, neural network-based device. Smears with abnormal PAPNET images were microscopically rescreened and then diagnosed by a U.S. cytopathologist. ThinPrep slides (Cytyc Corporation, Boxborough, MA), prepared from rinses of the cytologic sampler, and cervigrams (National Testing Laboratories, Fenton, MO) were also evaluated. Women with any abnormal cytologic diagnosis or a positive cervigram were referred for colposcopy with biopsy and definitive therapy if indicated. RESULTS: Based on the U.S. cytotechnologist's review of the PAPNET images, 1017 (13.9%) of 7323 smears were selected for manual screening, resulting in the selection of 492 (6.7%) possibly abnormal slides for referral to the U.S. pathologist. Ultimately, 312 smears (4.3% of the total) were diagnosed as containing squamous cells of undetermined significance or a more severe abnormality (> or =ASCUS), resulting, hypothetically, in the referral of 66.5% of women with a final diagnosis of a squamous intraepithelial lesion or a more severe abnormality (> or =SIL) and 86.0% of patients with > or =high grade SIL. Conventional microscopic screening performed in Costa Rica resulted in the hypothetical referral of 6.5% of patients with > or =ASCUS for colposcopy, including 69.5% of patients with > or =SIL and 79.8% of those with > or =high grade SIL. CONCLUSIONS: In this study, PAPNET-assisted cytologic screening accurately identified smears obtained from women with high grade SIL or carcinoma. Determination of the clinical cost-effectiveness of PAPNET-assisted screening in routine practice awaits future study.

Cohort Studies↗

Transcriptional activation of the type II transforming growth factor-beta receptor gene upon differentiation of embryonal carcinoma cells.

Previously, it has been shown that differentiation of embryonal carcinoma (EC) cells turns on the expression of functional transforming growth factor type-beta receptors. Here, we show that the type II receptor (TbetaR-II) gene is activated at the transcriptional level when EC cells differentiate. We show that the differentiated cells, but not the parental EC cells, express transcripts for TbetaR-II. In addition, the expression of TbetaR-II promoter/reporter gene constructs are elevated dramatically when EC cells differentiate and we identify at least two positive and two negative regulatory regions in the 5' flanking region of the TbetaR-II gene. Moreover, we identify a cAMP response element/activating transcription factor site that acts as a positive cis-regulatory element in the TbetaR-II promoter, and we demonstrate that the transcription factor ATF-1 binds to this site and strongly stimulates the expression of the TbetaR-II promoter/reporter gene constructs when ATF-1 is overexpressed in EC-derived differentiated cells. Equally important, we identify a negative regulatory element in a 53-base pair region that had previously been shown to inhibit strongly the expression of TbetaR-II promoter/reporter gene constructs. Specifically, we demonstrate that this region, which contains an inverted CCAAT box motif, binds the transcription factor complex NF-Y (also referred to as CBF) in vitro. Furthermore, expression of a dominant-negative NF-YA mutant protein, which prevents DNA binding by NF-Y, enhances TbetaR-II promoter expression. Together, these studies suggest that the transcription factors ATF-1 and NF-Y play important roles in the regulation of the TbetaR-II gene.

Activating Transcription Factor 1↗

Reversal and protection against indomethacin-induced blood stasis and mucosal damage in the rat jejunum by a beta3-adrenoceptor agonist.

BACKGROUND: In the rat, indomethacin causes jejunal villous shortening, microvascular distortion, and blood stasis prior to ulceration. The beta3-adrenoceptor agonist CL316,243 (CL) prevents both the early histological changes and ulceration. AIM: To test the hypothesis that the beta3-adrenoceptor agonist CL316,243 exerts its protective effect by prevention and/or reversal of blood flow changes in the rat jejunum exposed to indomethacin. METHODS: In anaesthetized rats, jejunal villous blood flow was measured in surface capillaries using fluorescence microscopy. Stasis of superficial capillary blood flow was induced by combined topical and i.v. indomethacin (100 microg/mL, 2.8 x 10(-4) M). To examine the effect of CL on blood stasis, CL was applied either i.v. (1 mg/kg) or luminally (100 microg/mL, 2.5 x 10(-5)M) at the onset of stasis. Prophylactic protection was assessed by giving i.v. CL simultaneously with indomethacin. Results were compared with controls which received luminal saline applied at blood stasis. The effect of i.v. CL (1 mg/kg) alone, or luminal CL (100 microg/mL) alone on basal villous blood flow was also examined. The small intestines were perfusion-fixed with 10% formol saline, and removed for histology, n = 5 for all groups. RESULTS: Luminal CL given at stasis reversed indomethacin-induced stasis within 10 min, whereas i.v. CL did not. Pretreatment with i.v. CL prevented the onset of stasis. Basal blood flow was raised slightly only by luminal CL. CONCLUSION: The beta-adrenoceptor agonist CL316,243 can protect against indomethacin-induced blood stasis in rat jejunal villi.

Adrenergic beta-Agonists↗

Caring and cancer nursing: framing the reality using selected social science theory.

Despite the recent interest in caring for both academic and clinical nursing, the theoretical basis of this concept may appear somewhat elusive as the research and debate vary widely in their focus. As a result, the available literature may fail to consider the specific contextual issues which characterize caring as it is understood across different health care settings. Consideration of theory from disciplines close to nursing, it is suggested, may be useful in understanding the nature of such 'real world' caring. In this discussion the concept of caring within cancer nursing is explored by drawing on a number of social science and nursing sources. It is known that cancer provokes unique caring demands for nurses practising in this area. By examining the context of cancer, it is argued that effective caring deserves to be recognized as an important clinical variable which can influence a diverse range of issues such as patient satisfaction or therapeutic outcome. It is suggested that other nursing specialisms should also explore the psychosocial dimensions of caring in relation to their own role.

Empathy↗

Depression, cognition, and functional correlates of recovery outcome after traumatic brain injury.

The present study investigated the prevalence and magnitude of depressive symptomatology in a sample of patients who had sustained traumatic brain injury (TBI) six months earlier. Depression was examined as a function of recovery outcome status, and its association with neuropsychological functioning, personal competency, and employability was also explored. Subjects were 100 patients who had previously sustained moderate-to-severe TBI who were enrolled as research subjects in the UCLA Brain Injury Research Center, and 30 matched control subjects who had sustained traumatic injuries other than to the head six months prior to evaluation. The results showed a significant association between depression and recovery status as measured by the Glasgow Outcome Scale (GOS). A significant majority of depressed subjects were found in the poorer GOS outcome groups (severe and moderate disability), compared to TBI subjects who had good GOS outcomes, and control subjects. This association was also reflected in the magnitude of the mean depression scores on two self-report measures of depression. However, no association was found between depression status and performance on the neuropsychological measures. Effects of depression were found only on an examiner-rated Patient Competency scale, and a metacognition measure based on self-report. These results are discussed in terms of brain injury severity, recovery status, and metacognition issues in TBI and other disorders.

Activities of Daily Living↗

Neuropsychological, psychosocial and vocational correlates of the Glasgow Outcome Scale at 6 months post-injury: a study of moderate to severe traumatic brain injury patients.

Traumatic brain injury (TBI) subjects at Glasgow Outcome Scale levels 3 (severe disability), 4 (moderate disability), 5 (good recovery), and an other-injury control group (OIC) were compared in terms of neuropsychological, psychosocial, and vocational functioning 6 months after injury. Subjects were a sample of 100 patients with a moderate to severe traumatic brain injury (TBI) and a matched sample of 30 other-injury control subjects (OIC) enrolled in the UCLA Brain Injury Research Center study of TBI outcome. Overall, the results showed a systematic decrease in mean neuropsychological test performance as a function of increasing GOS severity, as well as an increased prevalence of symptoms of depression and lower ratings on measures assessing employability and capacity for self care. TBI patients in the 'severe' and 'moderate disability' groups were distinctly inferior to the 'good recovery' and 'OIC' groups, who were quite similar to each other in terms of cognitive, psychosocial, and vocational outcomes. The results demonstrate overall support for the predictive and concurrent validity of the GOS 6 months post injury. Despite these results, which strengthen the utility and appeal of the GOS for multicentre studies, concerns still remain regarding GOS category 4 (moderate disability), which was shown to lack sufficient discriminability in this study.

Activities of Daily Living↗

Word Association Test and psychosexual cues in assessing persons with eating disorders.

The present study aimed to detect psychosexual conflicts in patients with eating disorders using the Word Association Test which tests the perceptual sensitivity of the subject to conflictual words. We also expected patients to show concern about food and eating. 19 anorexic patients, 21 bulimic patients, and 20 control subjects without eating disorders provided associations to four groups of words: psychosexual words, food words, emotionally loaded words, and neutral words. Reaction times were recorded. Analysis showed that anorexic patients were slower than controls in responding to food-related words but bulimic patients were not significantly different from controls. Anorexic patients reacted more slowly than controls to psychosexual words. Bulimic patients were also somewhat slower than controls but faster than anorexic patients; however, these differences were not statistically significant. Results are congruent with research that points to sexual problems and delays in the psychosexual development of anorexic patients and to a lesser extent of bulimic patients.

Adult↗

Immunolocalization of putative human liver progenitor cells in livers from patients with end-stage primary biliary cirrhosis and sclerosing cholangitis using the monoclonal antibody OV-6.

The term oval cell describes small cells with oval nuclei that arise in the periphery of the portal tracts in rat models of hepatocarcinogenesis and injury and can differentiate into either hepatocytes or bile duct cells, ie, are bipotential. The presence of such cells in human liver is controversial. Here, immunolocalization of OV-6 and two biliary markers, cytokeratin 19 (CK-19) and human epithelial antigen 125 (HEA-125) is compared in normal adult human livers and in primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) liver sections. CK-19 and HEA-125 stained bile ducts and ductules in normal liver as well as proliferating ductular structures in diseased livers. OV-6 did not label ducts or ductules in normal liver, but in PBC and PSC stained numerous proliferating ductular and periductular cells and lobular hepatocytes. In PBC, discrete OV-6-positive cells with a mature biliary-cell-like morphology were seen integrated into some intact bile ducts as well as occasional small immature oval-like cells. In addition, in PSC, hepatocytes in regenerating lobules were also strongly stained with OV-6, and on close inspection, in both PBC and PSC, oval cells and small hepatocytes at the margins of the lobules were strongly labeled. In contrast to the rat liver, OV-6 and CK-19 staining did not always co-localize. It is proposed that the small OV-6-positive oval cells are analogous to those seen in rat models and may represent human liver progenitor cells that may differentiate into OV-6-positive ductal cells or lobular hepatocytes.

Adolescent↗

Inactivation of the FGF-4 gene in embryonic stem cells alters the growth and/or the survival of their early differentiated progeny.

Previous studies have shown that early mouse embryos with both FGF-4 alleles inactivated are developmentally arrested shortly after implantation. To understand the roles of FGF-4 during early development, we prepared genetically engineered embryonic stem (ES) cells, which are unable to produce FGF-4. Specifically, we describe the isolation and characterization of ES cells with both FGF-4 alleles inactivated. The FGF-4-/- ES cells do not require FGF-4 to proliferate in vitro, and addition of FGF-4 to the medium has little or no effect on their growth. Thus, FGF-4 does not appear to act as an autocrine growth factor for cultured ES cells. We also demonstrate that FGF-4-/- ES cells, like their unmodified counterparts, are capable of forming highly complex tumors in syngeneic mice composed of a wide range of differentiated cells types, including neural tissue, glandular epithelium, and muscle. In addition, we demonstrate that the FGF-4-/- ES cells can differentiate in vitro after exposure to retinoic acid; however, the growth and/or survival of the differentiated cells is severely compromised. Importantly, addition of FGF-4 to the culture medium dramatically increases the number of differentiated cells derived from the FGF-4-/- ES cells, in particular cells with many of the properties of parietal extraembryonic endoderm. Finally, we demonstrate that there are differences in the RNA profiles expressed by the differentiated progeny formed in vitro from FGF-4-/- ES cells and FGF-4+/+ ES cells when they are cultured with FGF-4. Taken together, the studies described in this report indicate that certain lineages formed in vitro are affected by the inactivation of the FGF-4 gene, in particular specific cells that form during the initial stage of ES cell differentiation. Thus, ES cells with both FGF-4 alleles inactivated should shed light on the important roles of FGF-4 during the early stages of mammalian development and help determine why FGF-4-/- embryos die shortly after implantation.

Animals↗

Cervical specimens collected in liquid buffer are suitable for both cytologic screening and ancillary human papillomavirus testing.

BACKGROUND: Several new techniques have been developed to improve the sensitivity of cervical carcinoma screening and reduce equivocal cytologic diagnoses referred to as atypical squamous cells of undetermined significance (ASCUS). This study evaluates the effectiveness of combining two newly introduced diagnostic techniques: preparation of thin-layer cytologic slides from ThinPrep liquid buffer and selected Hybrid Capture testing for human papillomavirus (HPV) DNA. Because HPV DNA detection has been strongly associated with the presence of a cervical carcinoma precursor ("squamous intraepithelial lesion," or SIL), HPV testing might be useful for identifying women with ASCUS who have an underlying SIL. METHODS: Two hundred specimens demonstrating diverse cervical abnormalities were selected from a prospective population-based study of 9174 women conducted in Costa Rica. The entire cohort had been screened with conventional cervical smears; ThinPrep slides made from liquid buffer, PAPNET, a computerized slide reading system; and Cervicography. Patients with any abnormal screening test were referred for colposcopy, punch biopsy, and loop excision of cases with high grade cytologic abnormalities not explained by punch biopsy. For this investigation, the results of ThinPrep cytology and HPV testing alone and in combination were compared with the final diagnoses, with an emphasis on the detection of carcinoma and high grade SIL. RESULTS: The 200 subjects studied included 7 women with a final diagnosis of carcinoma, 44 with high grade SIL, 34 with low grade SIL, 51 with a variety of equivocal diagnoses, and 64 with normal diagnoses. A ThinPrep cytologic diagnosis of SIL or carcinoma was made in 39 (76%) of the 51 women with final diagnoses of high grade SIL or carcinoma. Hybrid Capture testing detected carcinoma-associated types of HPV DNA in 100% of women with carcinoma, 75% with high grade SIL, 62% with low grade SIL, 20% with equivocal final diagnoses, and 12% of normal women. If colposcopy referral had been limited to women with a ThinPrep diagnosis of SIL or a diagnosis of ASCUS associated with the detection of carcinoma-associated HPV DNA from the same vial, 100% of women with carcinoma and 80% with high grade SIL would have been examined. To achieve this high sensitivity in the entire population of 9174 women would have required the referral of about 7% of the population. The combined screening strategy would have performed marginally better than optimized conventional screening with referral of any abnormal cytology (ASCUS and above). CONCLUSIONS: A cervical carcinoma screening technique which uses a single sample for cytopathology and HPV testing to triage equivocal diagnoses may be promising if it proves to be cost-effective.

Carcinoma↗

Transcriptional regulation of the TGF-beta 2 gene in choriocarcinoma cells and breast carcinoma cells: differential utilization of Cis-regulatory elements.

Previous studies have shown that the transcription of the TGF-beta 2 gene is controlled by at least one negative and two positive regulatory regions in differentiated cells derived from both embryonal carcinoma cells and embryonic stem cells. The use of TGF-beta 2 promoter/reporter gene constructs has also identified a CRE/ATF motif near the TATA box that appears to heavily influence the transcription of the TGF-beta 2 gene. In this study, two choriocarcinoma cell lines, JAR and JEG-3, and the breast cancer cell line, MCF-7, were used to determine whether differences exist in the transcriptional regulation of the TGF-beta 2 gene. We demonstrated that both similarities and differences exist in the transcriptional regulation of this gene. Common to all cells examined to date, the positive regulatory region just upstream of the TATA box contains an essential CRE/ATF motif that binds at least one transcription factor, ATF-1, in gel mobility shift assays. However, we did not detect ATF-2 binding to this site with any of the nuclear extracts used. We also determined that the effect of the region between -187 and -78 (relative to the transcription start site) is cell type dependent. Previous studies have shown that this region acts to reduce the activity of the TGF-beta 2 promoter in differentiated cells derived from embryonal carcinoma cells and embryonic stem cells. In direct contrast, this region acts as a strong positive regulatory region in JAR, JEC-3, and MCF-7 cells. The mechanisms responsible for these differing effects remain to be established. Interestingly, this region does not appear to contain sequence motifs that bind known transcription factors. Thus, this region is likely to bind one or more novel transcription factors or contain novel recognition sites for known transcription factors.

Activating Transcription Factor 1↗

Protection against oral and gastrointestinal diseases: importance of dietary nitrate intake, oral nitrate reduction and enterosalivary nitrate circulation.

Over the last 20 years, dietary nitrate has been implicated in the formation of methemoglobin and carcinogenic nitrosamines in humans. This has led to restrictions of nitrate and nitrite levels in food and drinking water. However, there is no epidemiological evidence for an increased risk of gastric and intestinal cancer in population groups with high dietary vegetable or nitrate intake. A reevaluation of our currently very negative perception of dietary nitrates comes from recent research into the metabolism and enterosalivary circulation of nitrate in mammals. These studies showed that nitrate is converted to nitrite in the oral cavity that then "fuels" an important mammalian resistance mechanism against infectious diseases. Moreover, there is now evidence that the conversion of nitrate into oxides of nitrogen prevents the formation carcinogenic nitrosamines.

Animals↗