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PubMed1994

Case managers and physicians: communication and perceived problems.

OBJECTIVE: To describe case managers' perceptions of the physician-case manager relationship. DESIGN: A qualitative field study using in-depth open-ended interviews was used to elicit case managers' experiences and practices. A multidisciplinary team analyzed transcripts using an adaptation of the "grounded theory" approach of Glaser and Strauss. PARTICIPANTS/SETTING: Case managers were selected for interview using a maximum variation sampling strategy within an established state-wide case management agency. MAIN OUTCOME MEASURES: Transcript analysis allowed for the organization of observations into themes, which were merged across interviews to generate theses. RESULTS: Case managers report that: (1) The case manager role is poorly understood by physicians. (2) Physicians lack insight into the social and environmental aspects of home-bound elderly people. (3) Access to physician services is often difficult to obtain. (4) Power struggles occasionally surface in care planning. (5) Decisions by physicians and case managers regarding the care of frail elderly are often made from different agenda. CONCLUSIONS: From the perspective of case managers, gaps in interprofessional communication may hinder the optimal care of frail elderly individuals.

Aged↗

PubMed1987

Spatial localization in NMR spectroscopy in vivo.

Spatial localization techniques are necessary for in vivo NMR spectroscopy involving heterogeneous organisms. Localization by surface coil NMR detection alone is generally inadequate for deep-lying organs due to contaminating signals from intervening surface tissues. However, localization to preselected planar volumes can be accomplished using a single selective excitation pulse in the presence of a pulsed magnetic field gradient, yielding depth-resolved surface coil spectra (DRESS). Within selected planes, DRESS are spatially restricted by the surface coil sensitivity profiles to disk-shaped volumes whose radii increase with depth, notwithstanding variations in the NMR signal density distribution. Nevertheless, DRESS is a simple and versatile localization procedure that is readily adaptable to spectral relaxation time measurements by adding inversion or spin-echo refocusing pulses or to in vivo solvent-suppressed spectroscopy of proton (1H) metabolites using a combination of chemical-selective RF pulses. Also, the spatial information gathering efficiency of the technique can be improved to provide simultaneous acquisition of spectra from multiple volumes by interleaving excitation of adjacent planes within the normal relaxation recovery period. The spatial selectivity can be improved by adding additional selective excitation spin-echo refocusing pulses to achieve full, three-dimensional point resolved spectroscopy (PRESS) in a single excitation sequence. Alternatively, for samples with short spin-spin relaxation times, DRESS can be combined with other localization schemes, such as image-selected in vivo spectroscopy (ISIS), to provide complete gradient controlled three-dimensional localization with a reduced number of sequence cycles.

Animals↗

PubMed1976

Location of stretch receptors in the trachea and bronchi of the dog.

1. Using single fibre vagal afferent recording techniques, we have investigated the longitudinal and circumferential location of slowly adapting stretch receptors in a functionally isolated, in situ segment of the trachea in dogs. 2. We have also studied the depth of these receptors within the airway wall and their response to reflex and drug induced contraction of the airway smooth muscle. 3. Thirty-four per cent of the receptors studied were in the extrathoracic trachea; calculations indicate that about 17-1% of all airway stretch receptors lie outside the thorax. 4. All the receptors were located in the membranous posterior wall of the trachea, and those tested responded more to transverse than to longitudinal stretching of the wall. 5. Receptors in the extrathoracic trachea continued to function after the regional mucosa had been widely resected; subsequent removal of histolocially proven smooth muscle tissue caused the abrupt cessation of receptor discharge. 6. Contraction of airway smooth muscle brought about an increase in receptor discharge frequency. 7. Similar results were found for a smaller number of stretch receptors located in the mainstem and lobar bronchi. 8. These findings procided evidence that stretch receptors are anatomically located within the smooth muscle layer of the airways and are functionally aranged in series with the muscle fibres.

Action Potentials↗

PubMed1984

High-pressure-temperature gradient instrument: use for determining the temperature and pressure limits of bacterial growth.

A pressurized temperature gradient instrument allowed a synoptic determination of the effects of temperature and pressure on the reproduction of bacteria. The instrument consisted of eight pressure vessels housed parallel to each other in an insulated aluminum block in which a linear temperature gradient was supported. For a given experiment, eight pressures between 1 and 1,100 bars were chosen; the linear temperature gradient was established over an interval within -20 to 100 degrees C. Pure cultures and natural populations were studied in liquid or solid medium either in short (ca. 2-cm) culture tubes or in long (76.2-cm) glass capillaries. In the case of a pure culture, experiments with the pressurized temperature gradient instrument determined values of temperature and pressure that bounded its growth. Feasibility experiments with mixed populations of bacteria from water samples from a shallow depth of the sea showed that the instrument may be useful in identifying the extent to which a natural population is adapted to the temperatures and pressures at the locale of origin of the sample. Additional conceived uses of the instrument included synoptic determinations of cell functions other than reproduction and of biochemical activities.

Bacteria↗

PubMed2005

Evolution of temporal order in living organisms.

Circadian clocks are believed to have evolved in parallel with the geological history of the earth, and have since been fine-tuned under selection pressures imposed by cyclic factors in the environment. These clocks regulate a wide variety of behavioral and metabolic processes in many life forms. They enhance the fitness of organisms by improving their ability to efficiently anticipate periodic events in their external environments, especially periodic changes in light, temperature and humidity. Circadian clocks provide fitness advantage even to organisms living under constant conditions, such as those prevailing in the depth of oceans or in subterranean caves, perhaps by coordinating several metabolic processes in the internal milieu. Although the issue of adaptive significance of circadian rhythms has always remained central to circadian biology research, it has never been subjected to systematic and rigorous empirical validation. A few studies carried out on free-living animals under field conditions and simulated periodic and aperiodic conditions of the laboratory suggest that circadian rhythms are of adaptive value to their owners. However, most of these studies suffer from a number of drawbacks such as lack of population-level replication, lack of true controls and lack of adequate control on the genetic composition of the populations, which in many ways limits the potential insights gained from the studies. The present review is an effort to critically discuss studies that directly or indirectly touch upon the issue of adaptive significance of circadian rhythms and highlight some shortcomings that should be avoided while designing future experiments.

Journal Article↗

PubMed2004

Performance of a write-once multilayer optical disk that uses transparent recording material with an optical switching layer.

A volumetric optical disk that has multiple transparent films with optical switching layers is used as a recording medium to increase the number of recording layers. In the disk the optical switching layer is adapted to reduce decay of laser energy and increase reading and recording sensitivity. Well-defined marks of approximately 100-nm depth can be placed precisely on the transparent films by a focused laser beam. Writing and reading of a four-layer recordable disk, fabricated by molding and spin bonding, have been demonstrated experimentally. The volumetric disk can achieve a high recording capacity with conventional optical pickups.

Journal Article↗

PubMed2005

Flowable resin used as a sealant in molars affected by dental fluorosis: a comparative study.

The decline in prevalence and incidence of dental caries in developed countries over the last two decades is considered to be due mainly to the widespread use of fluoride in different forms, but simultaneously with decline in caries, an increase in dental fluorosis has been reported. The aim of this study was to compare the Conventional Sealant Technique (CST) and Enameloplasty Sealant Technique (EST) using a flowable resin as sealant in molars affected by dental fluorosis. A total of 40 extracted third molars affected by dental fluorosis were divided at random into two groups of 20 teeth each, and Tetric Flow resin was used as sealant. All teeth were studied for lateral adaptation and resin penetration by direct and indirect techniques; all samples were replicated in epoxy resin and were evaluated with Scanning Electron Microscopy (SEM). The results demonstrated that EST allowed a deeper sealant penetration and a superior sealant adaptation than CST, both in direct and indirect evaluations by SEM. The most important variables being penetration-interface and penetration depth both being statistically significant (p<0.05). The CST did not flow into the bottom of the fissures, leaving spaces that can favor the fracture of the material and initiate the process of dental caries. We conclude that a flowable ceromer is an excellent material alternative to be used as sealant and that EST is quite necessary in molars affected by dental fluorosis, the combination of both being a reliable method to be used as primary prevention approach of dental caries in endemic areas of dental fluorosis.

Fluorosis, Dental↗

PubMed1986

Gross anatomy in medical education.

The present state of human gross anatomy in medical education can generally be characterized as the presentation of a large bolus of information that is swallowed and only partly digested during the first year of medical school. The subject is often taught in a depth beyond that which would be relevant to all physicians irrespective of their future professional careers. This condition has resulted from adaptive adjustments to the escalating discrepancy between a rapidly expanding knowledge base in science and technology and the relatively fixed time period for education of a physician. Initially, traditional courses retained their comprehensive character, and new information was simply piled on top of existing departmental offerings. It soon became obvious that there would have to be a reduction in time devoted to established courses and a reciprocal expansion of time to accommodate newly developing sciences. Such adjustments were painful and often led to conflicts about what comprises essential knowledge in medical education. Thus, the curriculum time devoted to human gross anatomy has been significantly reduced to accommodate new knowledge in cellular and sub-cellular structures and other disciplines. That common foundation of knowledge, skills, values, and attitudes essential to all physicians regardless of specialty is ever-changing and often debated by medical school faculty members. However, two facts are generally agreed upon: that today's medical student with a broad but perhaps thin base in science and limited direct clinical experience is not competent upon graduation to assume patient care responsibilities without supervision and that as a result, the formal education of a physician has expanded into the graduate domain.(ABSTRACT TRUNCATED AT 250 WORDS)

Anatomy↗

PubMed1990

Glaucomatous visual field damage. Luminance and color-contrast sensitivities.

Using a modified Humphrey perimeter, we evaluated 16 eyes with primary open-angle glaucoma and visual field loss (defects 0.5-3.0 log units in depth), and 14 normal eyes. Each eye was tested twice in random order with conventional luminance-increment static perimetry and with the perimeter modified to produce a high-luminance yellow adapting background and a blue test stimulus. The background was a broad-spectrum light of 500 nm and above (yellow), while the stimulus was a broad-spectrum light of 500 nm and below (blue). Paired comparisons were made between conventional and blue/yellow sensitivities for every point examined (1184 points in 16 diseased eyes and 1036 points in 14 normal eyes). Defect depths were determined by using the age-corrected norms distributed in the Humphrey Statpac software. In glaucomatous eyes, blue/yellow sensitivity showed greater impairment than did conventional perimetric sensitivity, in which defect depths were less than 1.0 log unit. However, for defects greater than 1.0 log unit in depth, conventional perimetric sensitivity and blue/yellow sensitivity showed equivalent degrees of damage. Receiver operating characteristic (ROC) analysis was used to compare the ability of blue/yellow and of conventional perimetry in distinguishing between glaucomatous and normal eyes. Results indicated that although blue/yellow color-contrast perimetry may be more sensitive for the detection of incipient glaucomatous damage, in the manifest stages of visual field damage blue/yellow color-contrast perimetry is no more sensitive than is conventional (luminance-increment) perimetry for defining the extent of glaucomatous visual field defects.

Adult↗

PubMed2002

Shading and texture: separate information channels with a common adaptation mechanism?

We outline a scheme for the way in which early vision may handle information about shading (luminance modulation, LM) and texture (contrast modulation, CM). Previous work on the detection of gratings has found no sub-threshold summation, and no cross-adaptation, between LM and CM patterns. This strongly implied separate channels for the detection of LM and CM structure. However, we now report experiments in which adapting to LM (or CM) gratings creates tilt aftereffects of similar magnitude on both LM and CM test gratings, and reduces the perceived strength (modulation depth) of LM and CM gratings to a similar extent. This transfer of aftereffects between LM and CM might suggest a second stage of processing at which LM and CM information is integrated. The nature of this integration, however, is unclear and several simple predictions are not fulfilled. Firstly, one might expect the integration stage to lose identity information about whether the pattern was LM or CM. We show instead that the identity of barely detectable LM and CM patterns is not lost. Secondly, when LM and CM gratings are combined in-phase or out-of-phase we find no evidence for cancellation, nor for 'phase-blindness'. These results suggest that information about LM and CM is not pooled or merged--shading is not confused with texture variation. We suggest that LM and CM signals are carried by separate channels, but they share a common adaptation mechanism that accounts for the almost complete transfer of perceptual aftereffects.

Adaptation, Ocular↗

PubMed2000

Corneal optical coherence tomography before and immediately after excimer laser photorefractive keratectomy.

PURPOSE: To investigate the representation of the corneal structure with optical coherence tomography before and immediately after excimer laser photorefractive keratectomy. METHODS: Twenty-four eyes of 24 patients with myopia and myopic astigmatism were prospectively studied. The corneal thickness and the corneal profile were assessed with slit-lamp-adapted optical coherence tomography preoperatively and immediately after excimer laser photorefractive keratectomy. RESULTS: The attempted mean spherical equivalent of the refractive corrections was -6.7 +/- 3.6 (mean +/- SD) diopters with a mean calculated stromal ablation depth of 91 +/- 38 microm. The corneal optical coherence tomography was reproducible in all patients, demonstrating a mean decrease of central corneal thickness after epithelial debridement and excimer laser photorefractive keratectomy of 118 +/- 45 microm. The comparison of the calculated stromal ablation depth and the corneal thickness changes determined by corneal optical coherence tomography revealed a significant linear relationship with a correlation coefficient of 0.88 (P <.001). The flattening of the corneal curvature was confirmed in all patients with the optical coherence tomography system and correlated with the attempted refractive correction (r =.82, P <.001). CONCLUSIONS: The slit-lamp-adapted optical coherence tomography system presented in this study allowed noncontact, cross-sectional, and high-resolution imaging of the corneal configuration. This initial clinical evaluation demonstrated that corneal optical coherence tomography could be a promising diagnostic modality to monitor corneal changes of thickness and curvature before and after excimer laser photorefractive keratectomy.

Adult↗

PubMed2025

LYCEUM: learning to call copy number variants on low-coverage ancient genomes.

MOTIVATION: Copy number variants (CNVs) are pivotal in driving phenotypic variation that facilitates species adaptation. They are significant contributors to various disorders, making ancient genomes crucial for uncovering the genetic origins of disease susceptibility across populations. However, detecting CNVs in ancient DNA (aDNA) samples poses substantial challenges due to several factors: (i) aDNA is often highly degraded; (ii) contamination from microbial DNA and DNA from closely related species introduces additional noise into sequencing data; and finally, (iii) the typically low-coverage of aDNA renders accurate CNV detection particularly difficult. Conventional CNV calling algorithms, which are optimized for high-coverage read-depth signals, underperform under such conditions. RESULTS: To address these limitations, we introduce LYCEUM, the first machine learning-based CNV caller for aDNA. To overcome challenges related to data quality and scarcity, we employ a two-step training strategy. First, the model is pre-trained on whole genome sequencing data from the 1000 Genomes Project, teaching it CNV-calling capabilities similar to conventional methods. Next, the model is fine-tuned using high-confidence CNV calls derived from only a few existing high-coverage aDNA samples. During this stage, the model adapts to making CNV calls based on the downsampled read depth signals of the same aDNA samples. LYCEUM achieves accurate detection of CNVs even in typically low-coverage ancient genomes. We also observe that the segmental deletion calls made by LYCEUM show correlation with the demographic history of the samples and exhibit patterns of negative selection inline with natural selection. AVAILABILITY AND IMPLEMENTATION: LYCEUM is available at https://github.com/ciceklab/LYCEUM.

DNA Copy Number Variations↗

PubMed2000

Differential jejunal and colonic adaptation due to resection and IGF-I in parenterally fed rats.

Patients with severe short-bowel syndrome (SBS) often require long-term total parenteral nutrition (TPN) to maintain their nutritional status because of limited intestinal adaptation. Growth factors, including insulin-like growth factor I (IGF-I), are under investigation to promote intestinal adaptation and tolerance to oral feeding. We investigated structural and functional adaptation of the jejunum and colon in four groups of rats maintained with TPN for 7 days after a 60% jejunoileal resection and cecectomy or sham surgery and treatment with IGF-I or vehicle. Resection alone did not stimulate jejunal growth. IGF-I significantly increased jejunal mucosal mass, enterocyte proliferation, and migration rates. IGF-I decreased jejunal sucrase specific activity and reduced active ion transport and ionic permeability; resection alone had no effect. In contrast, resection significantly increased colonic mass and crypt depth but had no effect on active ion transport or ionic permeability. IGF-I had minimal effects on colonic structure. IGF-I but not resection stimulates jejunal adaptation, whereas resection but not IGF-I stimulates colonic growth in rats subjected to a model for human SBS. IGF-I treatment may improve intestinal adaptation in humans with SBS.

Acclimatization↗

PubMed2004

Integration of overseas Registered Nurses: evaluation of an adaptation programme.

BACKGROUND: The growth in overseas nurse recruitment to address staff shortages in the United Kingdom (UK) has led to the proliferation of adaptation programmes for overseas nurses to gain appropriate experience and enable them register with the Nursing and Midwifery Council. This paper reports on selected findings from an independent evaluation of an adaptation programme for overseas Registered Nurses offered by a large acute National Health Service trust. AIM: This paper reports on a study to evaluate the programme with reference to its objectives, outcomes and overall success from the perspective of various stakeholders. METHODS: A pluralistic evaluation research model was adopted to identify the criteria that stakeholders used to judge the success of an adaptation programme, and then to use these criteria to judge the programme in question. Data were collected by means of focus group and individual in-depth interviews with overseas nurses, ward managers, mentors, senior nurse managers and educators over a 12 month period and analysed by drawing on the principles of dimensional analysis. The criteria for success identified by the various stakeholders provided a framework through which the overall success of the initiative could be judged. FINDINGS: Five meanings of success were identified: gaining professional registration; fitness for practice; reducing the nurse vacancy factor; equality of opportunity and promoting an organizational culture that values diversity. Key findings relating to each of these are presented. The ease with which nurses gained UK registration and integrated into the nursing workforce was influenced by the characteristics of the work environment, level of support, and organizational context. CONCLUSION: Industrialized nations recruiting from the global nursing market need to invest in providing appropriate support to enable overseas nurses to adapt to working in a different health care system and social and cultural context.

Accreditation↗

PubMed2006

Listeria monocytogenes: a multifaceted model.

The opportunistic intracellular pathogen Listeria monocytogenes has become a paradigm for the study of host-pathogen interactions and bacterial adaptation to mammalian hosts. Analysis of L. monocytogenes infection has provided considerable insight into how bacteria invade cells, move intracellularly, and disseminate in tissues, as well as tools to address fundamental processes in cell biology. Moreover, the vast amount of knowledge that has been gathered through in-depth comparative genomic analyses and in vivo studies makes L. monocytogenes one of the most well-studied bacterial pathogens.

Actins↗

PubMed2006

Cancer outcomes measurement: Through the lens of the Medical Outcomes Trust framework.

BACKGROUND: In 2001, the U.S. National Cancer Institute established the Cancer Outcomes Measurement Working Group (COMWG) to evaluate and advance the state of the science in patient-reported outcome (PRO) measurement, with a focus on health-related quality of life (HRQOL). To guide its work, the COMWG adopted the revised Medical Outcomes Trust (MOT) attributes and review criteria for evaluating health status and quality-of-life instruments. OBJECTIVE: With the MOT attributes providing the organizing principle, this paper summarizes and draws inferences from key COMWG findings about the methodological soundness of HRQOL assessment in cancer and steps required to move the field forward. RESULTS AND CONCLUSIONS: Across a range of cancer research applications, especially clinical trials, a variety of generic, general cancer, and cancer site-specific measures of HRQOL have demonstrated adequate reliability, validity, responsiveness, feasibility, and cultural and language adaptation. Methodological challenges remain in the interpretability of HRQOL measures, though substantial progress has been made in defining a "minimum important difference" in scale scores. Much work remains in forging a stronger link between the conceptual model and measurement model in HRQOL instrumentation. Progress along all MOT attributes will likely accelerate with the growing application of modern psychometrics, particularly item response theory modeling, which provides the underpinnings for item banking and computer-adaptive assessment of HRQOL. Future research should emphasize prospectively designed studies to evaluate PRO measures within the MOT framework and in-depth investigations of the role of PRO measures in cancer decision making at all levels.

Endpoint Determination↗

PubMed1990

Alkali-soluble and insoluble fluoride in erupted and unerupted sound enamel of human third molars in vivo.

The amounts of firmly and loosely bound fluoride were determined in sound enamel of unerupted and erupted teeth which had been exposed in vivo for 1-16 yr to brushing at least once a day, and occasionally to mouth rinsing and the application of sealers. Enamel was sampled by an acid-etch procedure, and the fluoride levels were measured with an adapted fluoride ion-selective electrode. Unerupted enamel was etched significantly (p less than 0.05) deeper than erupted enamel up to a depth of at least 8 microns. Significant differences (p less than 0.05) were found between the mean enamel fluoride concentrations of unwashed and alkali-washed, erupted teeth up to a depth of at least 3 microns and also between unwashed or washed, erupted versus unwashed or washed, unerupted teeth. At a depth of 3 microns, the fluoride treatments of enamel had increased the total amount of fluoride by approx. 78% of which approx. 53% was loosely bound fluoride (like CaF2) and 47% firmly bound (like fluorapatite). No increase in sound enamel fluoride as a result of topical treatments over a period of up to 16 yr could be found at a level deeper than 20 microns.

Acid Etching, Dental↗

PubMed1993

New bougie applicator system for intraluminal "high dose rate" afterloading radiotherapy of esophageal carcinoma.

Applicators used to date in endoluminal "high dose rate" (HDR) afterloading (AL) radiotherapy of esophageal carcinoma consist of hollow plastic probes with an average thickness of 4 mm (1.8-5.0 mm), the diameter of which, however, often strongly deviates from that of the lumen of the tumor stenosis. Consequently, the probe can occupy an eccentric position in the esophagus. Exact dosimetry in the tumor region thus becomes virtually impossible, since the dose of the iridium emitter drops significantly with increasing distance (> 60% at a distance of 5 mm from the surface of the 4 mm probe). The bougie-type afterloading applicators developed by our group, however, offer a number of distinct advantages in comparison to conventional applicator probes: 1. Precise positioning of the applicator in the stenosis with simultaneous bougie effect. 2. Exact centering of the radiation source in the lumen of the esophagus. 3. Individual adaptation of the applicator size to the diameter of the residual lumen resulting from the tumor. 4. Upon patient-specific adaptation of the radiation exposure period, a distinct reduction of the surface (mucosa) dose is achieved together with simultaneous enhancement of the depth effect of radiotherapy treatment. Using these new afterloading bougies in over 150 treatment sessions involving 55 patients, no complications were thus far observed.

Brachytherapy↗