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At least 577 records · Page 32Linked to original sources

PubMed1992

[Contact cyclophotocoagulation with the continuous wave Nd:YAG laser with quartz fiber. Optimizing coagulation parameters].

Transscleral cyclo-photocoagulation with a cw-Nd:YAG-laser was studied in enucleated porcine eyes with application times of between 10 ms and 1.5 s. Contact coagulation via a quartz fiber (core 600 microns) required about 32% less power to create visible ciliary body coagulation compared to non-contact coagulation via a focusing handpiece. Application of focusing fiber tips led to a further reduction in the coagulation threshold by a factor of 0.6. The energy per laser application required for ciliary body coagulation increased with application time. During contact coagulation using plane fiber tips a pronounced temperature rise was sometimes observed at the fiber tip due to deposits of carbonized tissue with the subsequent risk of scleral damage. In a pilot study five eyes with secondary glaucoma were treated under coagulation conditions found to be optimal (8 W at 0.2 s).

Anesthesia, Local↗

PubMed2003

[The role of synthetic hydroxyapatite solution in the destructive process of arteriosclerosis].

Presented work is a pilot research on dissolving of homogeneous synthetic hydroxyapatite, being chemically analogous to the hydroxyapatite formed in human organism. Crystallization of hydroxyapatite (HA) in human arteries also known as calcification is a complex process leading to dysfunctions in the functioning of human blood system and--in effect--to dysfunction in functioning of tissues and organs [1]. Mineralization of blood vessels is a complicated process and can appear in two forms: visible and hidden, which can be organic or inorganic [2]. With inorganic mineralization there are concerned primarily phosphoranes of Calcium, mostly apathites, while the organic mineralization is represented by organic substances like cholesterol, fats, lipids [2, 3]. The forming of crystals, fats, lipids etc. in arteries is an effect of continuation of the processes started by hidden mineralization [1]. Research was focused on the possibilities of dissolving the visible, inorganic mineralization, represented by synthetic hydroxyapatite. In the work, there are presented preliminary results of biochemical studies on dissolving of the synthetic hydroxyapatite. The processes of dissolving of this compound took place in dynamic conditions. The organic solutions of hawthorn, onion and garlic of various concentrations--2.5%, 5%, 7.5%--were used as the solvents. These herbs show anti-calcification effects. The preliminary results of the experiments confirm the hypothesis that the solutions of these herbs free the Ca and P ions from the grains of synthetic HA (in varying flowing pH and speed conditions). This research encourages further analysis of the processes of dissolving hydroxyapatite--either synthetic or coming from human body.

Antioxidants↗

PubMedDate not supplied

Vessel enhancement filtering in three-dimensional MR angiography.

For a variety of reasons, small vessels have low signal intensity in magnetic resonance angiography. When the vessel signal intensity is lower than the signal intensity of background tissues, these vessels tend not to be visible on maximum-intensity-projection images. The authors developed a nonlinear second-difference spatial filtering technique that enhances the details of small vessels while suppressing both noise and uniform background tissue. Two similar nonlinear second-difference filters are presented and compared with the linear Laplacian second-difference filter. To evaluate the performance of these filters, they were applied to intracranial three-dimensional time-of-flight MR angiographic data and the results compared with the vessel enhancement obtained with a simple second-difference Laplacian filter and with magnetization transfer contrast (MTC) techniques. The comparisons demonstrated that nonlinear filtering and MTC techniques result in similar improvement in small-vessel visibility and apparent continuity. A quantitative comparison demonstrated that the improvement in the contrast-to-noise ratio is much greater with the nonlinear filters than the Laplacian filter.

Circle of Willis↗

PubMed2003

The use of observation in the psychoanalytic treatment of a 12-year-old boy with Asperger's syndrome.

The author describes some aspects of a once-weekly psychoanalytic psychotherapy of a 12-year-old boy diagnosed with Asperger's syndrome. The patient's emotional and cognitive development had been impaired since early life, possibly due to an internal deficit and to the likelihood of inadequate environmental holding. He was unaware of having difficulties but was underachieving academically, was socially isolated and often visibly unhappy in his life. The patient's denial, splitting, and projection of emotion and insight presented the therapist with the difficult task of how to reach him. In order to communicate with him emotionally, the therapist created a modified technique which reflected the patient's development from part-object to whole-object relationships. This development became apparent in the sessions and was interpreted in the transference relationship. An account of the patient's early years was pieced together from a detailed commentary of what was being observed and intuited by the therapist during the sessions, as well as by an understanding of the countertransference. By the end of two years' treatment, the patient's sensitivity and creativity, which had been buried beneath a self-sufficient, autistic-like encapsulation, finally began to emerge in his communications with his therapist.

Asperger Syndrome↗

PubMed1992

Macular disease in an elderly population.

In order to obtain more accurate information concerning the prevalence of macular diseases in an elderly population, a clinical study was undertaken on a sample of 430 members of the general population over the age of 65 years in London. Degenerative age-related macular changes were clinically visible in about 25%, and 2.8% had a lesion causing loss of visual acuity due to macular disease. Age was the only risk factor identified for age-related changes. No correlation was identified with the prevalence of hypertension, smoking, or diabetes mellitus between groups. In addition, symmetry was shown in the number of drusen, as well as their size, density and fluorescence in the central and peripheral areas between the eyes of affected subjects. The prevalence data from this study represent a baseline for the interpretation of hospital-based data and for the planning of health care.

Aged↗

PubMed1976

Hairy cell leukemia (leukemic reticuloendotheliosis) II. Ultrastructure of the spleen.

Seven surgically removed spleens from patients with hairy cell leukemia and hypersplenism were examined ultrastructurally. In all spleens the pulp cords were diffusely and compactly infiltrated by hairy cells. Numerous hairy cells were also evident in the often distended sinuses. The hairy projections were readily visible in electron micrographs and tended to interdigitate to form syncytium-like aggregates. Compression of hairy cells within the cords flattened the projections against the cell bodies and may account for the surface alterations reported by scanning electron microscopic studies. Controversy over the cytogenesis of hairy cells has not been resolved by ultrastructural studies. Although all seven patients had hypersplenism, the hairy cells showed no evidence of phagocytic activity. However, active phagocytosis by cordal macrophages was observed and there is a probable absolute increase in their number contributing to the splenomegaly. The dense infiltrate of hairy cells causes marked widening of the cords and retards the passage of formed elements of the blood through the red pulp. Prolonged sojourn of these elements in a metabolically unfavorable environment results in cellular damage, increased exposure to cordal macrophages, and premature destruction with the evolution of a hypersplenic syndrome.

Humans↗

PubMed2004

Reinventing the apprenticeship: the hot seat in the digital era.

RATIONALE AND OBJECTIVES: Describe new interactive digital teaching methods for medical student education in radiology and evaluate student responses. MATERIALS AND METHODS: Third- and fourth-year medical students on radiology clerkship were taught using either film-based "hot seat" format, digital "hot seat," or didactic slide-based format. Digital hot seat included direct projection of full-resolution images and use of digital tablet for annotation. Students completed surveys commenting on each method. RESULTS: Before 2003-2004, comments were available from general course surveys. Only positive responses were made regarding digital hot seat format. Dedicated surveys of teaching methods since July 2003 (23 students) showed 100% gave high ratings to digital hot seat methods (1 or 2 on a scale from 1 to 5), citing easier visibility of findings and ability to draw on images as positive features. Fifty-two percent rated film hot seat method <3, with limited visibility as the main complaint. Didactic slide teaching was rated <3 by 74%. Eighty-three percent chose digital hot seat as their favorite format overall. CONCLUSIONS: Students overwhelmingly favor digital hot seat teaching over film-based or didactic slide presentations. Digital hot seat methods preserve the best features of case-based interactive teaching while improving visibility of findings.

Computer-Assisted Instruction↗

PubMed1999

Improving the detection of acetabular osteolysis using oblique radiographs.

Visualisation of periacetabular osteolysis by standard anteroposterior (AP) radiographs underestimates the extent of bone loss around a metal-backed acetabular component. We have assessed the effectiveness of standard radiological views in depicting periacetabular osteolysis, and recommend additional projections which make these lesions more visible. This was accomplished using a computerised simulation of radiological views and a radiological analysis of simulated defects placed at regular intervals around the perimeter of a cadaver acetabulum. The AP view alone showed only 38% of the defects over all of the surface of the cup and failed to depict a 3 mm lesion over 83% of the cup. When combined with the AP view, additional 45 degree obturator-oblique and iliac-oblique projections increased the depiction, showing 81% of the defects. The addition of the 60 degree obturator-oblique view further improved the visualisation of posterior defects, increasing the rate of detection to 94%. Based on this analysis, we recommend using at least three radiographic views when assessing the presence and extent of acetabular osteolysis.

Acetabulum↗

PubMed1994

The PEN & PAD medical record model: development of a nursing record for hospital-based care of the elderly.

The PEN & PAD Medical Record model describes a framework for an information model, designed to meet the requirements of an electronic medical record. This model has been successfully tested in a computer-based record system for General Practitioners as part of the PEN & PAD (GP) Project. Experiences of using the model for developing computer-based nursing records are reported. Results show that there are some problems with directly applying the model to the nursing domain. Whilst the main purpose of the nursing record is to document and communicate a patient's care, it has several other, possibly incompatible, roles. Furthermore, the structure and content of the information contained within the nursing record is heavily influenced by the need for the nursing profession to visibly demonstrate the philosophical frameworks underlying their work. By providing new insights into the professional background of nursing records, this work had highlighted the need for nurses to clarify and make explicit their uses of information, and also provided them with some tools to assist in this task.

Aged↗

PubMed1981

Visual perception of lifted weight.

The weight of a box can be seen by observing another person lifting and carrying it. Evidence is provided in two experiments, the first of which employed videotaped events with the actor and box visible only as 21 bright patches. Observers judged the weight of the box rather linearly with an average slope of .87 and with a pooled standard deviation of 3.8 kg. The second experiment compared visual and haptic perception of box weight in similar events under conditions of live action. Average slopes of 1.00 in the visual mode and 1.20 in the haptic mode were obtained with standard deviations of 3.1 kg and 2.0 kg, respectively. It is concluded that the weight of the box, as a dynamic variable of the event, is well specified in the kinematic pattern and hence in the optic array. Furthermore, the visual system is efficient in picking up such information.

Cues↗

PubMed1982

A new semiautomatic method for quantitative static and dynamic bone histology.

A new semiautomatic technique combining advantages of the manual and fully automatic methods is described for obtaining quantitative static and dynamic histologic data of bone. The hardware consists of a photomicroscope, digitizing platen, digitizer, plotter/printer, floppy disc drive, and computer. The microscope is equipped with a drawing tube through which the image of the digitizing platen is projected over the optical field. The investigator selects and traces all histologic structures to be measured by moving a cursor on the digitizing platen which is visible by its projection over the histologic field. The results on accuracy and static and dynamic precision of this method show that static and dynamic parameters of bone are obtained with a degree of error (less than 20%) well within the acceptable range for biologic measurements. Comparison of this method with the grid technique according to Merz and Schenck showed that for almost all micromorphometric parameters comparable absolute data are obtained. Due to the higher precision of our method, however, the number of optical fields evaluated in obtaining these comparable data could be reduced to 25% of the number of fields evaluated by the Merz and Schenck technique. The time requirements for quantitative evaluation of a histologic slide of bone by our technique are 40-50 min; 20-25 min is needed for quantitative evaluation of osteocytes.

Bone Resorption↗

PubMed2000

Sclerosing papillary carcinoma of the thyroid with tubular features.

A case of papillary thyroid carcinoma (PTC) in a twenty-seven year old female is reported. The patient presented with complaints of a goiter and associated dysphagia. Histologically, the tumor was characterized by diffuse growth of branching tubules lined by a single layer of the tumor cells and surrounded by circularly arranged fibrous tissue of variable thickness. Focally, micropapillary projections of the epithelium budding into the lumen of tubules were visible. The cells showed features of PTC (overlapping ground glass nuclei, multiple grooves and pseudoinclusions). Nevertheless, no areas of "classical" PTC were identified. A striking feature was the presence of a severe lymphoplasmocytic infiltrate and the presence of plentiful S-100 protein positive dendritic/Langerhans cells. The tumor shares several features with diffuse sclerosing PTC, namely the age and sex of the patient, the infiltrative growth pattern and the presence of severe chronic thyroiditis that is associated with a large number of dendritic/Langerhans cells in the background. There are, however, several distinct differences - particularly the absence of massive squamous metaplasia, psammoma bodies, areas of classical PTC, and also lack of invasion of lymphatic vessels. We believe that this tumor represents an unusual example of diffuse sclerosing PTC with special tubular features.

Adenocarcinoma↗

PubMed1993

Advanced multiple beam equalization radiography (AMBER) combined with computed radiography. Preliminary evaluation.

The combined use of AMBER (Advanced Multiple Beam Equalization Radiography) and a digital storage phosphor (SP) radiography system was evaluated for chest radiography in a pilot study with 4 patients. Four image modes with different dose levels were compared: the SP in combination with an AMBER equalized exposure (SP/AMBER) and 3 nonequalized exposures with dose levels corresponding to the respective calculated AMBER lung dose (SP/lung field dose), the calculated AMBER mediastinal dose (SP/mediastinal dose) and the calculated AMBER average dose (SP/average dose). All image modes were matched for Hurter and Driffield characteristics and subjectively rated according to visibility of details. The improved signal-to-noise (S/N) ratio of SP/AMBER resulted in a better visualization of structures in the mediastinum and the basal lung where SP/lung field dose scored lowest. For the central lung no quality differences were seen between techniques. The compressed dynamic range of the SP/AMBER images was more easily displayed on the hard-copy film. The combination of AMBER with SP radiography promises to overcome the dynamic range limitations of digital displays while, at moderate doses, giving better S/N and image quality than standard SP technique.

Adult↗

PubMed2001

Evaluation of the Thai-Lao Collaborating Nursing Manpower Development Project using the Context Input Process Product model.

The purpose of this article was to describe, monitor and evaluate the Thai-Lao Collaborating Nursing Manpower Development Project using Stufflebeam's Context Input Process Product model. The study found that the project had great success in personnel development according to the six activities of the project. It helped develop two nurses with Masters degrees, 24 senior nurses and 283 diploma and auxiliary nurses. There were visible changes in the discipline and in terms of nursing care, nursing process was utilized. The Lao nursing system was developed to the point where white uniforms were used as the symbol of nurses who previously went unrecognized. There was a change in the structure of nursing organization. Moreover, nursing activities moved towards the goal of health promotion and prevention. The study recommended that a periodic supervisory activity be implemented to enhance the training of trainers. In addition, a 2-year continuation program for Bachelor degrees in nursing should be developed initially in Laos, then a 4-year program should be developed. The nursing education program for Masters degrees should initially be obtained through neighboring countries.

Career Choice↗

PubMedDate not supplied

Electronic scanning-slit fluorography: design and performance of a prototype unit.

Electronic scanning-slit fluorography involves replacing paired fore and aft slits for scatter rejection with only one beam-defining tantalum fore aperture. Since the video signal within the projection of the aperture on the image intensifier is much more intense than behind the tantalum, one can discriminate electronically between these two signals and thus eliminate the unwanted x-ray scatter and veiling glare. The general features of a prototype unit are described along with the rationale for the choice of design factors employed. Imaging time of 1-2 s has been achieved using multiple scanning slits. Small focal-spot size and large number of pixels are favored for higher dose utilization, shorter imaging time, and lower x-ray tube loading, as well as for better spatial resolution. Images of a chest phantom show better visibility of low-contrast details, especially in poorly penetrated areas, when compared with the image obtained and displayed under the same conditions, but using a conventional grid to reject scattered radiation.

Biophysical Phenomena↗

PubMed2003

[The smile line, a literature search].

Beautiful teeth, visible when smiling, are in line with the present ideal of beauty. The display of teeth when smiling is determined by the smile line: the projection of the lower border of the upper lip on the maxillary teeth when smiling. On the basis of a literature search the determining methods of the smile line are discussed, demographic data of the position of the smile line are given, and factors of influence are examined. There is no unequivocal method for determining the position of the smile line. A rough distinction can be made between qualitative and (semi)-quantitative methods. The (semi)-quantitative methods have clear advantages for research purposes, but their reliability is unknown. It was demonstrated that among minimally 40% of subjects the maxillary gingiva was not visible when smiling. The mandibular gingiva was not visible when smiling among more than 90% of subjects. Furthermore, it appeared that among women the smile line was on average higher situated than among men and that it has not yet been proven that the smile line will be situated lower when growing older.

Age Factors↗

PubMed1985

Posterior polymorphous corneal dystrophy: a disease characterized by epithelial-like endothelial cells which influence management and prognosis.

This thesis contains a clinical and laboratory summary of findings in PPMD and, for the first time, reports the results of a large series of patients who underwent keratoplasty surgery. Posterior polymorphous dystrophy is bilateral and autosomal dominantly inherited. Slit lamp findings include corneal edema in the more advanced cases, calcific and lipid degenerative changes in severe cases, band-like lesions at the level of Descemet's membrane, localized or diffuse thickenings of Descemet's membrane, posterior corneal vesicular-like lesions, islands of abnormal cells surrounded by normal-appearing endothelial cells. Iridocorneal adhesions ranged in severity from fine or broad-based adhesions seen only on gonioscopy to large iridocorneal adhesions often associated with a glass-like membrane that are seen easily by slit lamp examination. All patients with broad-based iridocorneal adhesions have elevated intraocular pressure. Some patients have elevated pressure but no adhesions. Laboratory examination of corneal, iris, and trabecular meshwork tissue from patients undergoing penetrating keratoplasty and filtering operations reveals an abnormal endothelial cell layer covering the posterior cornea and growing across the trabecular meshwork and onto the iris. Although this tissue contains a variety of cells, the most prominent type is an epithelial-like cell. Extensive laboratory studies demonstrate features in common between the epithelial-like cells and normal epithelium. These include a multilaminar pattern, desmosomal junctions, microvillous projections, cytoplasmic keratin, sparse mitochondria, and rapid growth in tissue culture. These cells appear to determine the management and prognosis of patients with PPMD undergoing surgery. Twenty-two corneal transplants were performed on 20 eyes of 13 patients with PPMD. Their ages ranged from 11 to 77 years. The follow-up time after keratoplasty averaged 4.75 years. Nine grafts (41%) failed. Two failed because of an endothelial rejection, three because of glaucoma, one because of a retrocorneal membrane, two from both a retrocorneal membrane and glaucoma, and one from both an endothelial rejection and glaucoma. Thus, glaucoma was involved in six of the nine failures (27% of all grafts). Clinically visible retrocorneal membranes formed in 4 of the 22 grafts. All four eyes had preoperative slit lamp-visible iridocorneal adhesions. The factor that most prominently influences keratoplasty prognosis is the presence of iridocorneal adhesions.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed2002

Detection of in vitro demineralization of primary teeth using quantitative light-induced fluorescence (QLF).

INTRODUCTION: With the advent of remineralizing therapies and the new, conservative approach to restoration placement, interest in detecting and monitoring subclinical, precavitated lesions has increased. The increased understanding of clinicians about the processes of primary and secondary prevention and the detection of lesions to which these therapies may be applied, is one of the current goals in caries management. Quantitative light-induced fluorescence (QLF) is a new method for the detection of very early caries. OBJECTIVES: To determine the ability of QLF to detect and longitudinally monitor in vitro enamel demineralization. To present the device to the paediatric community and present future in vivo uses of the device. DESIGN: An in vitro study with combined in vivo pilot. SAMPLE AND METHODS: Twelve previously extracted, caries free, primary molars were selected and prepared. Two teeth were randomly selected as controls. Teeth were prepared by gentle pumicing and coating in an acid-resistant nail-varnish, except for an exposed window on the buccal surface. QLF baseline images were taken and the teeth then exposed to a demineralizing solution. Teeth were removed at regular intervals (24, 48, 72, 96, 120, and 144 h), air-dried and QLF images taken. QLF images were analysed by a single, blinded examiner (to control, to length of exposure). Mineral loss, as measured by DeltaQ, was recorded. RESULTS: Demineralization was noted in all experimental teeth by 48 h, and within 24 h in six teeth. The QLF successfully monitored the increase in mineral loss over time (P < 0.05). The detected lesions were not visible clinically until 144 h and then in only the most severe lesions. No demineralization was detected by QLF in control teeth. The device was user- and patient-friendly in vivo, detecting subclinical lesions. CONCLUSION: Detection of very early mineral loss and subsequent monitoring of this loss is possible in primary teeth using QLF. The device is well suited to use in paediatric dentistry and offers applications for both clinicians and researchers. The determination of the status of carious lesions (active/inactive) will be possible with readings taken at recall appointments.

Analysis of Variance↗