Systematic review of endoscopic ultrasound in gastro-oesophageal cancer.
Explore the source record for details and available documents.
Data Interpretation, Statistical↗
Biomedical subjects
K M Harris
Publications and source records attributed to K M Harris.
Paternal involvement with adolescents in intact families: the influence of fathers over the life course.
We measure the quality and quantity of fathers' involvement with adolescent children in intact families over time using longitudinal data from The National Survey of Children. We examine differentials in fathers' involvement by children's and family characteristics and model the long-term effects of fathers' involvement on children's outcomes in the transition to adulthood. Fathers are more involved with sons than with daughters and they disengage from adolescents with increasing marital conflict. We find beneficial effects for children of father's involvement in three domains: educational and economic attainment, delinquent behavior, and psychological well-being. The course of affective relations throughout adolescence also has a beneficial effect on delinquent behavior and psychological well-being.
Adaptation, Psychological↗
Who is the marginal patient? Understanding instrumental variables estimates of treatment effects.
OBJECTIVE: To clarify the issues of generalizability arising from the use of instrumental variable (IV) methods to estimate treatment effects in nonexperimental medical outcome studies. DATA SOURCE: We generate Monte Carlo data designed to resemble typical data sets where detailed health status information is unavailable and the treatment assignment process is unobserved. The model used to generate our data makes the realistic assumption that unobservable health status characteristics of patients influence the treatment assignment process and the effectiveness of treatment. STUDY DESIGN: We use Monte Carlo data to illustrate the circumstances where IV estimates generalize to an unobservable patient subpopulation and those where IV estimates generalize to the entire patient population represented by the sample used in the analysis. We also simulate the effect of two policy changes that affect practice patterns. Further, we show that IV estimates are useful for predicting the effect of these changes on treatment effectiveness when the subpopulation to which the IV estimate refers is the same or very similar to the population whose treatment status is affected by the policy change. CONCLUSIONS: Health services researchers cannot take for granted that IV estimates generalize to the same population represented by the sample used for analysis. Instead, researchers must rely on their knowledge of clinical practice and theory regarding the treatment assignment process in interpreting their results and in predicting the effect of changes in practice patterns.
Analysis of Variance↗
Improvement in mitral regurgitation after aortic valve replacement.
This study sought to determine whether there is a quantitative improvement in mitral regurgitation (MR) after aortic valve replacement (AVR) for aortic stenosis (AS) and, if so, the mechanisms for this change. MR frequently accompanies AS. The addition of mitral valve replacement to AVR significantly increases the risk of surgery. Although previous studies have suggested a qualitative improvement in MR severity after AVR, semiquantitative analysis of this improvement has not been documented nor have the underlying mechanisms been examined. We evaluated 28 patients who had undergone 2-dimensional echo and color flow Doppler imaging an average of 1.5 +/- 2.5 months before and 2.5 +/- 4.2 months after AVR. Maximum MR area, MR percentage (MR area/left atrial area), mitral annular area, left atrial area, aortic gradient, and parameters of left ventricular geometry were measured to evaluate MR severity and to assess functional mechanisms for improvement in MR. There was a significant decrease in MR area (5.5 +/- 2.8 cm2 vs 2.5 +/- 1.9 cm2, p < or =0.0001) and MR percentage (25 +/- 11% vs 12 +/- 10% after operation, p < or =0.0001) between preoperative and postoperative studies. There was a significant reduction in aortic gradient, mitral annular area, left atrial area, and left ventricular length postoperatively. In univariate analysis, MR improvement was related to the lower preoperative left ventricular fractional area change (p = 0.027) and to the changes in fractional area change (p = 0.001) and left ventricular systolic area (p = 0.001). Thus, improvement in MR after AVR is related to changes in left ventricular function postoperatively. These data suggest that reduction in MR is due not only to decreased intraventricular pressure, but also to changes in ventricular morphology.
Aged↗
Protecting adolescents from harm. Findings from the National Longitudinal Study on Adolescent Health.
CONTEXT: The main threats to adolescents' health are the risk behaviors they choose. How their social context shapes their behaviors is poorly understood. OBJECTIVE: To identify risk and protective factors at the family, school, and individual levels as they relate to 4 domains of adolescent health and morbidity: emotional health, violence, substance use, and sexuality. DESIGN: Cross-sectional analysis of interview data from the National Longitudinal Study of Adolescent Health. PARTICIPANTS: A total of 12118 adolescents in grades 7 through 12 drawn from an initial national school survey of 90118 adolescents from 80 high schools plus their feeder middle schools. SETTING: The interview was completed in the subject's home. MAIN OUTCOME MEASURES: Eight areas were assessed: emotional distress; suicidal thoughts and behaviors; violence; use of 3 substances (cigarettes, alcohol, marijuana); and 2 types of sexual behaviors (age of sexual debut and pregnancy history). Independent variables included measures of family context, school context, and individual characteristics. RESULTS: Parent-family connectedness and perceived school connectedness were protective against every health risk behavior measure except history of pregnancy. Conversely, ease of access to guns at home was associated with suicidality (grades 9-12: P<.001) and violence (grades 7-8: P<.001; grades 9-12: P<.001). Access to substances in the home was associated with use of cigarettes (P<.001), alcohol (P<.001), and marijuana (P<.001) among all students. Working 20 or more hours a week was associated with emotional distress of high school students (P<.01), cigarette use (P<.001), alcohol use (P<.001), and marijuana use (P<.001). Appearing "older than most" in class was associated with emotional distress and suicidal thoughts and behaviors among high school students (P<.001); it was also associated with substance use and an earlier age of sexual debut among both junior and senior high students. Repeating a grade in school was associated with emotional distress among students in junior high (P<.001) and high school (P<.01) and with tobacco use among junior high students (P<.001). On the other hand, parental expectations regarding school achievement were associated with lower levels of health risk behaviors; parental disapproval of early sexual debut was associated with a later age of onset of intercourse (P<.001). CONCLUSIONS: Family and school contexts as well as individual characteristics are associated with health and risky behaviors in adolescents. The results should assist health and social service providers, educators, and others in taking the first steps to diminish risk factors and enhance protective factors for our young people.
Adolescent↗
Visualization of the distribution of autophosphorylated calcium/calmodulin-dependent protein kinase II after tetanic stimulation in the CA1 area of the hippocampus.
Autophosphorylation of calcium/calmodulin-dependent protein kinase II (CaMKII) at threonine-286 produces Ca2+-independent kinase activity and has been proposed to be involved in induction of long-term potentiation by tetanic stimulation in the hippocampus. We have used an immunocytochemical method to visualize and quantify the pattern of autophosphorylation of CaMKII in hippocampal slices after tetanization of the Schaffer collateral pathway. Thirty minutes after tetanic stimulation, autophosphorylated CaM kinase II (P-CaMKII) is significantly increased in area CA1 both in apical dendrites and in pyramidal cell somas. In apical dendrites, this increase is accompanied by an equally significant increase in staining for nonphosphorylated CaM kinase II. Thus, the increase in P-CaMKII appears to be secondary to an increase in the total amount of CaMKII. In neuronal somas, however, the increase in P-CaMKII is not accompanied by an increase in the total amount of CaMKII. We suggest that tetanic stimulation of the Schaffer collateral pathway may induce new synthesis of CaMKII molecules in the apical dendrites, which contain mRNA encoding its alpha-subunit. In neuronal somas, however, tetanic stimulation appears to result in long-lasting increases in P-CaMKII independent of an increase in the total amount of CaMKII. Our findings are consistent with a role for autophosphorylation of CaMKII in the induction and/or maintenance of long-term potentiation, but they indicate that the effects of tetanus on the kinase and its activity are not confined to synapses and may involve induction of new synthesis of kinase in dendrites as well as increases in the level of autophosphorylated kinase.
Animals↗
Images in clinical medicine. Aortic intramural hematoma.
Explore the source record for details and available documents.
Aged↗
Three-dimensional organization of smooth endoplasmic reticulum in hippocampal CA1 dendrites and dendritic spines of the immature and mature rat.
Recent studies have shown high levels of calcium in activated dendritic spines, where the smooth endoplasmic reticulum (SER) is likely to be important for regulating calcium. Here, the dimensions and organization of the SER in hippocampal spines and dendrites were measured through serial electron microscopy and three-dimensional analysis. SER of some form was found in 58% of the immature spines and in 48% of the adult spines. Less than 50% of the small spines at either age contained SER, suggesting that other mechanisms, such as cytoplasmic buffers, regulate ion fluxes within their small volumes. In contrast, >80% of the large mushroom spines of the adult had a spine apparatus, an organelle containing stacks of SER and dense-staining plates. Reconstructed SER occupied 0.001-0.022 microm3, which was only 2-3.5% of the total spine volume; however, the convoluted SER membranes had surface areas of 0.12-2.19 microm2, which were 12 to 40% of the spine surface area. Coated vesicles and multivesicular bodies occurred in some spines, suggesting local endocytotic activity. Smooth vesicles and tubules of SER were found in continuity with the spine plasma membrane and margins of the postsynaptic density (PSD), respectively, suggesting a role for the SER in the addition and recycling of spine membranes and synapses. The amount of SER in the parent dendrites was proportional to the number of spines and synapses originating along their lengths. These measurements support the hypothesis that the SER regulates the ionic and structural milieu of some, but not all, hippocampal dendritic spines.
Aging↗
Breast care consultation center: role of the pathologist in a multidisciplinary center.
The Breast Care Consultation Center (BCCC) is a multidisciplinary center providing, in a single setting, a complete outpatient facility for women who have been diagnosed with or suspected of having breast cancer. A team of specialists are available to provide comprehensive, diagnostic (radiologist, surgeon, and pathologist), therapeutic (surgeon, radiotherapist, and medical oncologist), and support options. The pathologist, as a member of the diagnostic team, evaluates the material obtained or received at the BCCC. These include fine-needle aspirations (FNAs) obtained on-site as well as previously prepared cytohistological specimens. The pathologist renders the diagnosis following examination of the material and consultation with the multidisciplinary team. Thus, this approach is conducive for appropriate and accurate diagnosis where all data are available. In addition, the pathologist discusses the findings of each patient in the multidisciplinary conference. One thousand four hundred eighteen patients were evaluated at Magee-Womens Hospital BCCC from February 1992 through December 1994, during which time 366 FNAs were performed. The accuracy for positive diagnosis was 100%. Six negative cases had cancer on histology; these were due to sampling error (the lesion was missed). A multidisciplinary team is ideal for the evaluation of breast lesions that are suspicious for malignancy as it provides one-stop shopping and same-day diagnosis and therapeutic decisions.
Aged↗
Transesophageal echocardiographic evaluation of aortitis.
Aortitis is an uncommon infection which may occur in patients with preexisting atherosclerotic disease of the aorta. The clinical features in two patients presenting with fever and nonspecific symptoms are reviewed. In these patients, transesophageal echocardiographic features of wall thickening and false aneurysm formation were suggestive of the diagnosis of aortitis. Both patients were taken for surgical excision of the descending aorta and subsequently improved.
Aneurysm, Infected↗
Transesophageal echocardiographic and clinical features of aortic intramural hematoma.
OBJECTIVE: This study sought to determine the transesophageal echocardiographic features and natural history of patients with aortic intramural hematoma. METHODS: The transesophageal echocardiograms of all patients who had symptoms indicative of aortic dissection over 6 years were reviewed. Measurements were made of the involved aortic segment in the study patients, and follow-up was obtained. RESULTS: In patients with aortic intramural hematoma, the wall thickness of the involved segment was significantly greater for descending segments than ascending segments (ascending aorta 7 +/- 2 mm, descending aorta 15 +/- 6 mm, p = 0.0016). In each case, the crescent-shaped intramural hematoma involved one wall predominantly, leading to compression of the aortic lumen. The findings of echolucent areas and displaced intimal calcium were found in the majority of patients. Four of eight patients with intramural hematoma of the ascending aorta were treated medically and four were treated surgically. The 30-day mortality was 50% in the medically treated patients and 0% in the surgically treated group. Four of 11 patients with isolated intramural hematoma of the descending aorta were treated medically and seven were treated surgically. All medically treated and 86% of surgically treated patients were alive at 30 days. CONCLUSIONS: Aortic intramural hematoma has distinct and identifiable transesophageal echocardiographic features. These data support those of previous studies documenting high morbidity and mortality in patients with aortic intramural hematoma.
Aged↗
Recurrent ovarian tumor with low malignant potential and cardiac metastasis.
BACKGROUND: Up to 20% of ovarian epithelial tumors are classified as being of low malignant potential. Most of these low malignant potential tumors are detected at an early stage and have an excellent prognosis. This is a report of a woman with cardiac metastasis from an ovarian low malignant potential tumor. CASE: This case describes a 53-year-old woman who presented with congestive heart failure and was found to have a recurrent stage III ovarian tumor of low malignant potential. A transesophageal echocardiogram revealed compression of the inferior vena cava and a mass encompassing the right atrium. Findings at autopsy confirmed a low malignant potential ovarian tumor thrombus involving the inferior vena cava and right atrium. CONCLUSION: Ovarian low malignant potential tumors can metastasize in an aggressive manner. A transesophageal echocardiogram may be useful when the diagnosis of cardiac tumor thrombus is considered.
Carcinoma↗
CREB: a major mediator of neuronal neurotrophin responses.
Neurotrophins regulate neuronal survival, differentiation, and synaptic function. To understand how neurotrophins elicit such diverse responses, we elucidated signaling pathways by which brain-derived neurotrophic factor (BDNF) activates gene expression in cultured neurons and hippocampal slices. We found, unexpectedly, that the transcription factor cyclic AMP response element-binding protein (CREB) is an important regulator of BDNF-induced gene expression. Exposure of neurons to BDNF stimulates CREB phosphorylation and activation via at least two signaling pathways: by a calcium/calmodulin-dependent kinase IV (CaMKIV)-regulated pathway that is activated by the release of intracellular calcium and by a Ras-dependent pathway. These findings reveal a previously unrecognized, CaMK-dependent mechanism by which neurotrophins activate CREB and suggest that CREB plays a central role in mediating neurotrophin responses in neurons.
Animals↗
Preliminary clinical evaluation of a high-resolution telemammography system.
RATIONALE AND OBJECTIVES: The authors designed, assembled, tested, and clinically evaluated a high-quality, fast, and relatively inexpensive telemammography system. METHODS: The authors designed a telemammography system that uses a high-resolution film digitizer and high data compression (> or = 40:1) to send images over regular telephone lines to a high-resolution laser printer that produces images with the look and feel of the original image and can operate in a hub and spokes mode. The authors then evaluated the system's performance. In a preliminary clinical study, interpretations of the laser-printed system's output of 119 cases were compared with the original interpretations, followed by a review of any clinically significant differences. RESULTS: With the exception of the laser printer, which is a modified off-the-shelf product, all hardware components of the system are commercially available products. The system digitizes (50 microns pixel size), compresses, transmits, receives, decompresses, and prints a 30 MB mammography file in less than 4 minutes. In the clinical study, there were 13 differences (in 13 cases) in the level of concern or recommendations. Seven were found to be clinically insignificant by a third-party review. The remaining six were reviewed by the original interpreter, and three were determined to be significant enough for further action. All were found to result from intra-reader variability rather than differences in visualization of possible abnormalities. CONCLUSIONS: Almost real-time, high-quality telemammography without geographic boundaries is possible with the use of high-level data compression. Telemammography with laser-printed film as the display may make it possible to offer mammographic services in remote locations while using commercially available technology.
Evaluation Studies as Topic↗
The identification of bias in studies of the diagnostic performance of imaging modalities.
The demand for evidence-based healthcare is increasing nationally and internationally and it is equally necessary in both diagnostic and therapeutic practice. Evidence may be collected and combined by means of a systematic literature review of published and unpublished data on a well-defined topic. The output of such reviews is then available to guide health policy, influence good practice or direct research. Published guidelines are available on the performance of systematic reviews, especially those of randomized controlled trials. Although there is an extensive literature base of research data in diagnostic imaging there are few such trials, but it is still possible to perform systematic reviews. With the alternative study designs encountered it is important to be aware of the main threats to study validity. In this paper the biases likely to be encountered in studies of diagnostic performance are reviewed, with particular reference to diagnostic imaging tests. The biases are sub-divided into three categories. The first category is patient selection and covers the validity of generalizing results beyond the study population. The other two, concerning study design and execution and the interpretation of results, affect the likely validity of the results of a study. An understanding of these factors is an essential prerequisite for those undertaking or using a systematic literature review in the field of diagnostic imaging. The definitions form the foundations of a defensible review protocol.
Bias↗
Distinguishing left ventricular aneurysm from pseudoaneurysm. A review of the literature.
A postmyocardial infarction left ventricular pseudoaneurysm occurs when a rupture of the ventricular free wall is contained by overlying, adherent pericardium. A postinfarction aneurysm, in contrast, is caused by scar formation resulting in thinning of the myocardium. Although the usual treatment for patients with pseudoaneurysm is urgent surgical repair, the imaging characteristics of pseudoaneurysm and aneurysm, for which treatment is more conservative, are quite similar. The literature on the natural history and imaging characteristics of the two entities is reviewed, and an approach to distinguishing between the two entities is proposed.
Aged↗
The orientation of first cleavage in the sea urchin embryo, Lytechinus variegatus, does not specify the axes of bilateral symmetry.
One blastomere of the two-cell stage sea urchin embryo (Lytechinus variegatus) was labeled with an intracellular fluorescent lineage tracing stain to determine, from the lineage of that blastomere, the orientation of the first cleavage furrow with regard to the axes of bilateral symmetry in the gastrula and pluteus larva. Two methods were used to mark the blastomere: in the first, the lipophilic carbocyanine dye DiIC16 was microinjected directly into the blastomere after first cleavage was completed. In the second, caged (nonfluorescent) fluorescein-dextran was microinjected into the single-celled zygote and uncaged (made fluorescent) in one of the blastomeres at the two-cell stage using two-photon excitation microscopy (TPEM). This is the first use of TPEM for embryonic lineage tracing. In both methods the dye proved to be nontoxic and fluorescence was confined to lineally related cells. The results from both methods were similar and showed that the first cleavage furrow was variable in its orientation. Results were similar using animals obtained from different geographic locations. These results differ from those of McCain and McClay (Development, 1994, 120, 395-404), who reported that the median orientation was invariant in this species. The differences between the two studies are discussed. We conclude that first cleavage does not specify nor is it predictive of the bilateral axes in this species. The technique of TPEM is proffered as a powerful new tool that will enable the marking and tracing of embryonic cell lineages with less injury and more precision than current methods.
Animals↗
The horizontal vertical illusion: evidence for strategic factors in feedback-induced illusion decrement.
This study assessed whether feedback would improve performance on a horizontal vertical illusion task and whether such improvement would transfer to different forms of the illusion. Subjects shortened the extended vertical line of small, medium, and large inverted-T figures to be equal in length to the horizontal line before and after being shown a correctly adjusted medium-sized figure (visual feedback). Next, they were tested on three alternate forms of the illusion; a production task (drawing 1-in. lines in the horizontal and vertical planes), an adjustment task using L figures, and a task requiring them to choose which of several sailboat drawings had mast height equal to hull length. Prior to feedback, vertical lines were adjusted shorter than the horizontal lines on each size inverted-T figure. After feedback on the medium-size figure, experimental subjects were more accurate than the controls on each size inverted-T figure. The results suggest that transfer of illusion decrement was also obtained for the boat-selection and, to a lesser extent, the L-figure adjustment tasks but not to the line-production task. These findings are consistent with the notion that improvement after feedback is not due to structural changes in visual processing or to simple feedback-induced compensation in performance but involves some strategic or cognitive change in judging line length.
Adult↗