SEARCH · PubMed Health

Results for “Deep Learning”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources

PubMed2006

[Partial or total replacement of the aortic arch. Experience in 23 patients].

BACKGROUND: Surgery of the aortic arch is a very complex procedure since it requires protective strategies for the brain, heart and rest of the body. AIM: To communicate our experience in the first 23 total or partial replacements of aortic arch. MATERIAL AND METHODS: Retrospective search in the database of the Cardiovascular Surgery Unit for patients subjected to partial or total replacement of the aortic arch since 1998. RESULTS: Between 1988 and 2002, 23 patients were operated. Seventeen had aortic dissection (10 acute and 7 chronic), five had an atherosclerotic aneurysm and one had a traumatic lesion. Thirteen patients were subjected to a replacement of the arch plus ascending aorta, six to a replacement of the arch plus descending aorta and four to a replacement of the arch, ascending and descending aorta. Seven patients had previous operation of the thoracic aorta. Arterial perfusion was done via the femoral artery, axillary artery or a combination of both. A hypothermic circulatory arrest was induced in 22; it was associated with cerebral retro perfusion alone in 8 patients, antegrade cerebral perfusion in 5; isolated or associated axillary perfusion was used in five patients. In seven, procedures on the aortic or mitral valve, or coronary artery operations were added. Operative mortality was 26%, 3 of the 8 patients operated as an emergency and 3 of 15 elective operations. There was no mortality among those without dissection and of 7 chronic dissections, one died. All patients were followed for an average of 45 months. Two patients required reinterventions on the aorta and one for colon cancer. There was one late death of unknown cause. Postoperative complications were agitation, bleeding and temporary vocal cord dysfunction. CONCLUSIONS: There is a learning curve, where more extensive operations, particularly those done as emergency or for dissections, had an increased operative risk.

Aortic Dissection↗

PubMed1994

CEO summit. The new delivery & financing realities. Part III of III.

In cooperation with McManis Associates Inc., Washington, Hospitals & Health Networks recently convened a summit on the integration of financing and delivery in health care. This installment is the third of a three-part series on lessons learned by those on the front lines of integration activity. The session was designed and facilitated by senior associates at McManis. Among the issues summit participants discussed in the second segment: What level of understanding do purchasers have of the factors that differentiate quality in health care services? Can provider-driven integrated delivery systems compete with insurer-driven ones? And what happens when a large integrated delivery system merges with a dominant insurer, as happened in the Philadelphia market? Can that model be successfully replicated in other markets? In this final segment, participants talk about whether providers' deep connections to their communities will add value in a reformed delivery system; how incentives might be aligned among all the players in integrated networks and organizations; how the concept of community focus might be redefined under systems integration; and the process involved in preparing for constant, accelerated change. The second segment concluded with comments about the assets providers and insurers bring to integrated health systems, and whether the merger experience of Graduate Health System and QCC/Independence Blue Cross could be replicated in other markets or not.

Community-Institutional Relations↗

PubMed2005

Estrogen with and without progestin: benefits and risks of short-term use.

Estrogen therapy has been well established as an effective treatment for relief of vasomotor symptoms. In light of recent evidence from large randomized trials showing serious risks associated with use of estrogen treatment, current recommendations for hormone therapy emphasize using the lowest effective dose for the shortest possible time. The purpose of this review is to examine what has been learned from the Women's Health Initiative (WHI) Hormone Trials and other studies about the short-term risks and benefits of estrogen use. A second purpose is to examine whether short-term risks differ for women most likely to use hormone treatment, including individuals with vasomotor symptoms; women in their 50s; and women, with and without intact ovaries, who have had a hysterectomy. During the first 1 to 2 years of use of conjugated equine estrogens alone (E-alone) or combined with medroxyprogesterone acetate (E + P), women experience an elevated risk of coronary heart disease, stroke, and deep vein thrombosis or pulmonary embolism. The magnitude of risk is greater for E + P than for E-alone. Fracture risk is not reduced with 1 to 2 years of use, but a fracture benefit is seen within 5 years of use. Increased risk of breast cancer does not appear until after 4 to 5 years of E + P use and was not increased with E-alone use after < or =7 years of treatment. This pattern of risks and benefits is generally similar for women with vasomotor symptoms, women in their 50s, and women, with and without > or =1 intact ovary, who have had a hysterectomy.

Estrogen Replacement Therapy↗

PubMed2003

A decision support system to detect morphologic changes of chromatin arrangement in normal-appearing cells.

Several studies have described malignancy-associated changes (MACs) of chromatin arrangement in the nuclei of apparently normal cells adjacent to and distant from an invasive cancer area. MAC assessment is a hard task, since it requires a deep knowledge of morphologic features of chromatin arrangement. The aim of this work is to verify the reproducibility of the subjective evaluation of the expert on the basis of a decision support system (DSS) that automatically and objectively reproduces MAC diagnosis. A set of 61 patients with suspected clinical diagnosis for lung cancer has been taken into account. The scientist who first described MAC defined each patient as MAC positive or negative on the basis of the MAC diagnosis performed on all cells of the related cytologic sample. A DSS based on an artificial neural network has been set up to learn the relation between 14 morphometric and texture parameters, computed on each nucleus by image processing techniques, with the MAC diagnosis of the expert on each cell. The results show that an objective automatic assessment on MAC by the DSS can effectively support the MAC diagnosis. The method adopted in this approach may be also appropriate for other problems, where an automatic classification of visually inspected patterns of biological micro- and submicrostructure is needed.

Algorithms↗

PubMed2000

Drugs for the gynecologist to prescribe in the prevention of breast cancer: current status and future trends.

Tamoxifen was approved for breast cancer prevention in October 1998. Thus, for the first time, we as gynecologists are being asked to prescribe this drug to healthy women. In the past each one of us has cared for women with breast cancer who have been treated with tamoxifen by oncologists or breast surgeons for the malignancy. Effects of tamoxifen on the uterus resulting in carcinomas, hyperplasia, and polyps are well known. Furthermore, tamoxifen has estrogenic properties in the venous system, increasing the incidence of deep vein thrombosis and pulmonary emboli. A new SERM (selective estrogen receptor modulator), raloxifene, has been approved for prevention and treatment of osteoporosis in postmenopausal women. It does not have stimulatory effects on the endometrium; however, it is estrogenic in the venous system. Preclinical data, as well as the breast cancer incidence reported in studies of the skeleton, seem to indicate that its effects in the breast are similar to those of tamoxifen. This article reviews tamoxifen and the new SERM, raloxifene, in an attempt to help gynecologists better understand each compound and what data are currently known, what we hope to learn from future studies, and what currently makes sense for clinical practice.

Breast Neoplasms↗

PubMed2004

[The dialogue between literature and medicine in the education of medical students].

On the basis of the conception that literature, like science, is an instrument of knowledge, the authors used some texts to underline the importance of dialogue between different disciplines. In particular, the discourse on the ethical significance of biomedicine fluctuates from the more established and deep ethics to the humanistic and anthropological ethics present in literature and vice versa. The aim of the work is to demonstrate that literature is an essential study for medical students. Thus, literature does offer the possibility to deepen the awareness of issues and experiences one cannot or will never have. An understanding of narrative can help clinicians and medical students in developing a dynamic relation with everyday complex stories of medical situations. The authors do believe that practising physicians should be encouraged to read critically; every medical and health care students need to be educated how to read in order to learn how to behave in everyday dialogue with patients and their relatives.

Education, Medical, Undergraduate↗

PubMed1997

Nerve supply of the breast with special reference to the nipple and areola: Sir Astley Cooper revisited.

Cooper in 1840 described mammary branches from the 2nd-6th intercostal nerves, and noticed that the nipple was supplied by branches which lay close to the surface of the gland. Eckhard (1850) divided the mammary branches into superficial branches to the skin and nipple, and deep branches to the glandular tissue and nipple, but many later authors ignored those findings. After the second World War, cosmetic surgery of the breast made further research critical, as surgeons strove to design operations which would retain its shape and preserve postoperative sensation. Craig and Sykes (1970) described mainly anterior branches from the 3rd, 4th and 5th intercostal nerves passing through the glandular tissue of the breast and along the line of the ducts to the nipple, while Farina et al. (1980) concluded that the nipple was supplied solely by superficial lateral branches of the 4th nerve. Using improvements in dissecting technique learned from microsurgery, Sarhadi et al. (1996) found that the nipple was innervated by the lateral cutaneous branch of the 4th intercostal nerve, by two branches, one passing superficial to the gland, and the other through the retromammary space, and by variable lateral and medial additional branches from the 2nd-5th nerves. These branches came to lie superficially and formed a subdermal plexus under the areola. This account is uncannily close to Cooper's original description; it is a reassuring, if sobering, conclusion that his early account remains one of the most reliable.

Anatomy↗

PubMed2004

Interactive web-based programs to teach functional anatomy: the pterygopalatine fossa.

Certain areas of the body contain structures that are difficult to envision in their proper spatial orientations and whose functions are complex and difficult to grasp. This is especially true in the head, where many structures are relatively small and inaccessible. To address this problem, we are designing Web-based programs that consist of high-resolution interactive bitmap illustrations, prepared using Adobe Photoshop, and vector-based animations, prepared via Macromedia Flash. Flash action script language is used for the animations. We have used this approach to prepare a program on the pterygopalatine fossa, an important neurovascular junction in the deep face that is especially difficult to approach by dissection and to depict in static images in an atlas. The program can be viewed online at http://cds.osr.columbia.edu/anatomy/ppfossa/. A table of contents simplifies navigation through the program and a menu enables the user to identify each of the vascular and neuronal components and either to insert or to remove each from its position in the fossa. The functional anatomy of the nerves in the fossa is animated. For example, users can activate and subsequently follow action potentials as they course along axons to their targets. This high degree of interactivity helps promote learning.

Anatomy, Cross-Sectional↗

PubMed1982

Cingulate cortical and anterior thalamic neuronal correlates of the overtraining reversal effect in rabbits.

Multiple-unit activity of the cingulate cortex and the anteroventral (AV) nucleus of the thalamus in rabbits was recorded during reversal training, following differential conditioning of a locomotory (wheel rotation) avoidance response. The CS+ and CS- were pure tones (1 or 8 kHz) and the UCS was a footshock delivered through the grid floor of the wheel. One group of the rabbits received original training to a criterion followed immediately by reversal training. A second group received training to criterion followed by additional training sessions (overtraining), prior to reversal training. The results indicated that the overtraining reversal effect (ORE) occurred. That is, the overtrained subjects acquired the reverse discrimination in significantly fewer sessions than the non-overtrained subjects. The overall (non-discriminative) neuronal reactivity in all cingulate cortical laminae was reduced by overtraining, whereas the overall reactivity of the AV thalamus was enhanced. In addition, the non-overtrained subjects manifested a discriminative neuronal response appropriate to the original task (i.e. a greater response to the CS- than to the CS+ for reversal training), throughout the precriterial sessions of reversal training. This persistent 'original habit effect' occurred only at brief latencies (20-30 msec) after CS onset, and only in the deep cortical laminae (V-VI). The neuronal activity of the superficial laminae (I-IV) in non-overtrained subjects underwent a transition, in parallel with the behavior, from a discriminative response appropriate to the original task to one appropriate to the reversal task. No significant training-related changes were seen at any cortical depth in the overtrained subjects. Presentation of non-contingent footshocks during two sessions of reversal training following criterion re-enhanced the overall reactivity and the brief-latency discriminative neuronal response appropriate to the original task, which had undergone decline during reversal training, in the deep cortical laminae of the non-overtrained subjects. The enhanced overall reactivity and the discriminative activity in the superficial laminae of non-overtrained subjects had not declined during reversal training and were not altered by the non-contingent footshocks. The implications of these data are discussed in regard to the neural causation of the ORE.

Animals↗

PubMed1998

Source localization of P300 from oddball, single stimulus, and omitted-stimulus paradigms.

Three different auditory stimulus paradigms were used to elicit P300 potentials. Normal subjects were tested on the classical rare target stimulus, single-stimulus and omitted-stimulus conditions. Noninvasive identification of the cerebral sources of the event-related potentials (ERPs) was performed using spatio-temporal multiple dipole modeling (BESA software) with individually sized spherical head models. The grand average data of each condition was first independently modeled and these models were used as starting values for modeling each individual subject's data. Models for the rare-stimulus condition and single-stimulus condition both consisted of 6 dipoles. Models for the omitted-stimulus condition consisted of 2 dipoles. The dipole locations of the final individual 6-dipole models for the rare and single-stimulus conditions did not differ significantly from each other or from one previous result obtained from a another group of subjects (Tarkka et al. 1995). Super-imposition of the dipole coordinates on the sterotaxic brain atlas suggests that bilateral deep medial temporal lobe structures are the major contributors to rare and single-stimulus P300s. Because both the wave form morphology and the source model of the P300 elicited by single stimulus were close to those of the rare-stimulus P300 it may be that the underlying neural mechanisms eliciting these P300 potentials are essentially the same.

Acoustic Stimulation↗

PubMed2000

The mammary gland-infant intestine immunologic dyad.

The human infant has a very small immune system and needs the support of the mother with the transplacentally arrived IgG antibodies to protect tissues with inflammatogenic and energy-consuming defense. The mucous membranes, where most infections occur, need support via the specialized secretory IgA antibodies and the many other mucosal defense mechanisms provided via the mother's milk. This defense is not inflammatogenic and energy-consuming. We learn about additional defense factors in the milk, like the anti-secretory factor, which seems to protect against diarrhoea. The milk contains numerous growth factors and cytokines, like leptin, which may promote the development of the intestine as well as the immune system. Results are appearing giving interesting evidence for enhanced protection against infection also after the termination of breastfeeding. This may occur via the priming of the infant's immune system after uptake of anti-idiotypic antibodies and lymphocytes from the milk. A breastfeeding motivation study in a large Pakistani village resulted in a 50% decrease of diarrhoea and infant mortality. Deep interviews with the mothers and the traditional birth attendants suggested that even better results may be obtained.

Adjuvants, Immunologic↗

PubMed2005

Loss of ovarian function and the risk of ovarian cancer.

Animal models with premature ovarian failure resulting from the loss or depletion of germ cells consistently develop ovarian surface epithelial cell hyperplasia with invasion into the stroma and the development of ovarian tubular adenomas. In human ovaries, deep epithelial invaginations and inclusion cysts occur at increasing frequency with age and are thought to be the structures from which the majority of ovarian cancers arise. A feature that is common to these animal models and to post-menopausal women is a deficiency in the number of oocytes. The potential consequences of the loss or depletion of female germ cells, naturally or otherwise, include failure of follicle development, significant reductions in oestrogen and progesterone levels and elevation of circulating levels of gonadotropins. This review will consider the way in which these structural and hormonal changes affect ovarian cancer risk. Some lessons may be learned from gonad formation, since notable similarities exist between ovarian tumorigenesis and embryonic gonadogenesis including fragmentation of the basement membrane underlying the coelomic (surface) epithelium, the potential for the migration of epithelial cells into the gonad and the importance of the germ cells for the regulation of ovarian structure and function.

Animals↗

PubMed1992

The cerebellum and the adaptive coordination of movement.

Based on a review of cerebellar anatomy, neural discharge in relation to behavior, and focal ablation syndromes, we propose a model of cerebellar function that we believe is both comprehensive as to the available information (at these levels) and unique in several respects. The unique features are the inclusion of new information on (a) cerebellar output--its replicative representation of body maps in each of the deep nuclei, each coding a different type and context of movement, and each appearing to control movement of multiple body parts more than of single body parts; and (b) the newly assessed long length of the parallel fiber. The parallel fiber, by virtue of its connection through Purkinje cells to the deep nuclei, appears optimally designed to combine the actions at several joints and to link the modes of adjacent nuclei into more complex coordinated acts. We review the old question of whether the cerebellum is responsible for the coordination of body parts as opposed to the tuning of downstream executive centers, and conclude that it is both, through mechanisms that have been described in the cerebellar cortex. We argue that such a mechanism would require an adaptive capacity, and support the evidence and interpretation that it has one. We point out that many parts of the motor system may be involved in different types of motor learning for different purposes, and that the presence of the many does not exclude an existence of the one in the cerebellar cortex. The adaptive role of the cerebellar cortex would appear to be specialized for combining simpler elements of movement into more complex synergies, and also in enabling simple, stereotyped reflex apparatus to respond differently, specifically, and appropriately under different task conditions. Speed of learning and magnitude of memory for both novel synergies and task-specific performance modifications are other attributes of the cerebellar cortex.

Adaptation, Physiological↗

PubMed2001

Menu design with visual momentum for compact smart products.

Users of compact smart products with small screens often have trouble learning the menu structure. If they cannot master the menu structure, users are not able to fully utilize the products. It is argued in this paper that using visual momentum in menu representation design helps users develop effective mental maps of menu structures and promotes learning of the user interface. To assess the effect of visual momentum in this study, four types of menu representations were developed. Additionally, two menu hierarchies, two types of function key layout, and two types of function key labeling were assessed to examine the effects of menu dimension and compatibility. Experimental results indicated that participants using a partial menu map with visual momentum design performed the best, and participants using a partial menu map without visual momentum performed the poorest, even worse than those-using command-only representation. The results also showed that the menu navigation problem appeared to be particularly significant with a deep menu hierarchy. Actual or potential applications of this research include menu representation design for compact smart products.

Adult↗

PubMed2005

Strategic intensity: a conversation with world chess champion Garry Kasparov.

It's hard to find a better exemplar for competition than chess. The image of two brilliant minds locked in a battle of skill and will-in which chance plays little or no apparent role-is compelling. Even people who have scant knowledge of the game instinctively recognize that chess is unusual in terms of its intellectual complexity and the strategic demands it places on players. Can strategists learn anything from chess players about what it takes to win? To find out, H BR senior editor Diane L. Coutu talked with Garry Kasparov, the world's number one player since 1984. Kasparov believes that success in both chess and business is very much a question of psychological advantage; the complexity of the game demands that players rely heavily on their instincts and on gamesmanship. In this wide-ranging interview, Kasparov explores the power of chess as a model for business competition; the balance that chess players strike between intuition and analysis; the significance of his loss to IBM's chess-playing computer, Deep Blue; and how his legendary rivalry with Anatoly Karpov, Kasparov's predecessor as World Chess Champion, affected his own success. Kasparov also shares his solution to what he calls the champion's dilemma, a question for all world masters, whether they are in business, sports, or chess: Where does a virtuoso go after he has accomplished everything he's ever wanted to, even beyond his wildest imagination? If you are lucky, says Kasparov, your enemies will push you to be passionate about staying at the top.

Commerce↗

PubMed2006

Does the effect of familiarity on proofreading change with encoding task and time?

The authors examined whether the beneficial effect of text familiarity on proofreading is dependent on the type of encoding operations performed on the text prior to proofreading (i.e., surface vs. deep), and on the time elapsed between encoding and proofreading. In the present study, familiarity, irrespective of the nature of the encoding operations and delay, improved proofreading times, whereas only surface encoding made proofreading more accurate. These results represent a challenge for the transfer-appropriate processing model of memory.

Attention↗

PubMed2003

Gene expression profiling in T-cell acute lymphoblastic leukemia.

T-cell acute lymphoblastic leukemia (T-ALL) presents a difficult medical problem. T-ALL's clinical features and the biological properties of the leukemia cells are not predictive of prognosis, and thus have not been useful for risk-specific adjustments in therapeutic intensity. Microarray gene expression analyses of T-cell leukemic lymphoblasts have not only improved our understanding of the biological heterogeneity of this disease but have revealed clinically relevant molecular subtypes. Five different multistep molecular pathways have been identified that lead to T-ALL, involving activation of different T-ALL oncogenes: (1) HOX11, (2) HOX11L2, (3) TAL1 plus LMO1/2, (4) LYL1 plus LMO2, and (5) MLL-ENL. Gene expression studies indicate activation of a subset of these genes-HOX11, TAL1, LYL1, LMO1, and LMO2-in a much larger fraction of T-ALL cases than those harboring activating chromosomal translocations. In many such cases, the abnormal expression of one or more of these oncogenes is biallelic, implicating upstream regulatory mechanisms. Among these molecular subtypes, overexpression of the HOX11 orphan homeobox gene occurs in approximately 5% to 10% of childhood and 30% of adult T-ALL cases. Patients with HOX11-positive lymphoblasts have an excellent prognosis when treated with modern combination chemotherapy, while cases at high risk of early failure are included largely in the TAL1- and LYL1-positive groups. Supervised learning approaches applied to microarray data have identified a group of genes whose expression is able to distinguish high-risk cases. Further analyses of gene expression signatures of T-ALL lymphoblasts are especially needed for patients treated on modern combination chemotherapy trials to clearly distinguish the 10% to 15% of patients who fail induction or relapse in the first year of treatment. These high-risk patients would be ideal candidates for more intensive therapies in first remission, such as myeloablative regimens with stem cell rescue. Based on the rapid pace of research in T-ALL, made possible in large part through microarray technology, deep analysis of molecular pathways should lead to new and much more specific targeted therapies.

Cell Differentiation↗

PubMed2003

[Surgery for morbid obesity: 2. Complications. Results of a Technologic Evaluation by the ANAES].

The frequency of bariatric surgery has increased markedly in France in recent years, partly due to a better appreciation of the problem of morbid obesity but also due to the commercial introduction of adjustable gastric banding devices which can be placed by laparoscopic approach. Numerous complications of this surgery are known and require recognition to be appropriately treated. Studies of complications suffer from selection bias, methodologic flaws, and lack of follow-up. The incidence and type of complication are affected by the learning curve and surgical techniques. Postoperative mortality varies from 0.14% for laparoscopic gastric banding (LGB), to 0.31% for vertical banded gastroplasty (VBGP) and 0.35% for Roux-en-Y gastric bypass (GBP); pulmonary embolus accounts for 60-70% of deaths in all groups combined. Early post-operative complications vary with specific procedures. Abdominal wall complications, already frequent in an obese population, are decreased from 10% for open procedures to 6% for laparoscopic gastric banding. Both VBGP and GBP are now being done laparoscopically with increasing frequency. Complications specific to LGB include gastric perforation (0.3%), or port problems (5%). Complications with VBGP and GBP include fistula (1-3%), deep abscess, and pulmonary embolus (2%). Global early morbidity is 4.2% for LGB, and varies from 6.4%-22% for VBGP and 6.2%-11.3% for GBP depending on laparoscopic versus open approach. Late mechanical complications are also specific to type of surgery. Pouch dilatation is the most common late complication of LGB (6.3%) and seems related both to operative experience and to site of placement of the band; it has decreased with higher positioning of the band to leave a minimal gastric pouch and with dissection through the pars flaccida of the lesser omentum instead of directly along the muscular wall of the stomach. It usually requires reintervention. Erosion of the gastric band into the stomach (1.6%) is often asymptomatic and is suggested by late weight gain. With VBGP, disruption of a gastric staple line occurs in 12.1% and stenosis of the outlet with proximal dilatation in 6.5%; erosion of the calibrating band of Marlex or silastic occurs in 2.7%. With GBP, the disruption of a staple line across an intact stomach (23%) has become less of a problem with division of the gastric pouch from the distal stomach (2%). Stenosis of the gastrojejunostomy (3.7%) and marginal ulcer (3.5%) are not uncommon. The incidence of wound hernia, obstructive adhesions, and late cholecystectomy vary with the length and thoroughness of follow-up. Late functional complications such as vomiting, dysphagia, heartburn and esophagitis vary with the quality and length of follow-up study. GBP may cause diarrhea and dumping syndrome. Nutritional complications are more common with GPB than with purely restrictive procedures; iron, folate, and Vitamin B12 deficiency are the rule with GBP and require routine replacement therapy; iron deficiency has been noted even with LGB. ate death seems more related to co-morbidities than to the intervention itself. Thorough long-term follow-up study of complications is indispensable for assessment of outcomes and improvement of laparoscopic techniques. Even the less traumatic surgical approach of laparoscopic band placement should not be considered free of risk; strict adherence to pre-operative surgical indications should be maintained.

Adult↗