Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Computer Peripherals”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 433 records · Page 24Linked to original sources
PubMed2003

Adenoviral VEGF-A gene transfer induces angiogenesis and promotes bone formation in healing osseous tissues.

BACKGROUND: Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis. VEGF has been safely and efficiently applied to stimulate neovascularization in ischemic tissues in atherosclerotic patients. VEGF has an important role in bone repair by promoting angiogenesis and by stimulating major skeletal cell populations, chondrocytes, osteoblasts and osteoclasts. METHODS: We studied the effect of VEGF-A on the recovery of bone drilling defects in rat femur delivered with first-generation adenoviral vector. The virus was injected into the muscle layer surrounding the bone defect made by drilling and the healing was followed for 1, 2, and 4 weeks. RESULTS: The VEGF effect was first demonstrated with an increased number of FVIII-related antigen-positive blood vessels in the defect area 1 week after the procedure. The proportional area of remaining reparative tissue was significantly reduced in the VEGF-treated animals 2 weeks after the injury suggesting favorable effect on bone healing. Increased periosteal cartilage was seen at the early phases of healing suggesting endochondral ossification. VEGF overexpression, however, completed the endochondral phase earlier compared with the control condition. Bone mineral content was enhanced in the VEGF-treated femurs measured with peripheral quantitative computed tomography at a 2-week time point. CONCLUSIONS: Our data confirm the important role of VEGF in bone healing. We show for the first time that adenoviral VEGF-A gene transfer may modify bone defect healing in a rodent model.

Adenoviridae↗
PubMed1994

Influence of steroid medication on bone mineral density in children with nephrotic syndrome.

Bone mineral density (BMD) was studied in 26 children with idiopathic nephrotic syndrome and in age- and sex-matched healthy controls. BMD was selectively measured in trabecular (TBD), cortical (CBD) and total bone (BD) using peripheral quantitative computed tomography. Patients showed a decrease in BD, CBD and TBD. BD and CBD were inversely correlated with the cumulative dose of steroid treatment. Of the 26 patients with high cumulative doses of steroid, 16 were also treated with cyclophosphamide. In this group BD and CBD were decreased significantly compared with the children with a low cumulative steroid dose only. Compared with controls for each subgroup, significant decreases in BD, CBD and TBD were found in the group with high cumulative doses of steroids only. The higher cumulative steroid dose and the initial steroid toxicity which made cytotoxic therapy necessary, rather than cyclophosphamide itself, may be responsible for these findings.

Adolescent↗
PubMed1995

Countinuous Laser-Doppler free-flap monitoring via the telephone line. Preliminary experiences.

It is possible to link a Laser-Doppler to a DOS-compatible personal computer in order to monitor microcirculation of the free flap after plastic surgery. We connected such a system to a second computer by telephone modems, in order to control the Laser-Doppler via the telephone line from a distant location using only commercially available hardware and software. The aim was to develop a low-cost system which would not require the purchase or construction of any specialised equipment. Using this system, it was possible to show the Laser-Doppler waveforms to colleagues who were not at the patient site, for their (more experienced) opinions without any further delays. Preliminary tests on five cases showed that it was indeed possible to transfer recorded information about the blood flow rate of free skin flaps from one computer to a remote one, without any loss of information. In these cases, the measured blood flow and clinical surveillance of the blood supply were adequate, thus making revision of the tissues not necessary. This preliminary study suggests that standard 'off-the-shelf' personal computer tools may be useful in improving the monitoring of microcirculation after plastic surgery.

Computer Peripherals↗
PubMed1991

Comparative accuracies of a finger blood pressure monitor and an oscillometric blood pressure monitor.

A noninvasive blood pressure monitor (Finapres) that uses the methodology of Penaz to continuously display the arterial waveform from the finger has been introduced recently. The Finapres monitor overestimated systolic pressure by 5.8 +/- 11.9 mm Hg, while the Dinamap monitor underestimated systolic pressure by -6.9 +/- 9.2 mm Hg (P = 0.003). Dinamap mean and diastolic pressure biases were less than 2 mm Hg, while the Finapres biases for these variables were significantly greater (7.7 +/- 10.0 and 8.2 +/- 9.8 mm Hg, respectively). There was no difference in systolic or mean pressure precision between the two devices (approximately 10 mm Hg), but the diastolic precision of the Dinamap unit was superior to that of the Finapres. While in most patients the Finapres monitor provided continuous blood pressure data equivalent to the data from the radial artery, marked bias (greater than 15 mm Hg) was exhibited in 2 patients for all three pressure variables. Despite this bias, blood pressure changes were tracked closely in these 2 patients. We conclude that, in its current form, the Finapres monitor cannot be relied upon independently to accurately measure blood pressure in patients undergoing general anesthesia. Since the Dinamap monitor measures mean pressure reliably and accurately, we suggest that mean blood pressure values between the Finapres and Dinamap monitors be compared to guide one in interpreting Finapres data.

Adolescent↗
PubMed1994

Monitoring of right ventricular function using a conventional slow response thermistor catheter.

OBJECTIVE: To investigate whether determination of right ventricular end-diastolic volume (RVEDV) and right ventricular ejection fraction (RVEF) can be performed with reasonable accuracy and reproducibility using a conventional slow response thermistor pulmonary artery catheter (CPAC) applying an adaptive algorithm. DESIGN: To study RVEDV and RVEF simultaneously with pulmonary artery catheters equipped with slow and fast response thermistors (FRPAC) under a broad range of cardiac output. SETTING: Laboratory of Institute of Experimental Surgery, Technical University. ANIMALS: 11 anaesthetised piglets. INTERVENTIONS: Hypovolemia (V-) was induced by withdrawal of blood up to 50 ml/kg, hypervolemia (V+) was produced by retransfusing blood and adding up to 30 mg/kg hydroxyethyl starch. In 5 animals in phases V- and V+ beta-adrenergic stimulation was achieved with dobutamine. Finally pulmonary artery hypertension was induced by infusion of small air bubbles. MEASUREMENTS AND RESULTS: Cardiac output (CO), RVEDV and RVEF were determined simultaneously with FRPAC and CPAC placed in the same pulmonary artery branch. Measurements were repeated 8 times sequentially in steady state normovolemia. A total of 130 measurements could be analysed. The coefficient of variation was 6.7 +/- 4.2% for CO(FRPAC) and 4.6 +/- 1.7% for CO(CPAC); for RVEF it was 9.7 +/- 6.2% (FRPAC) and 9.9 +/- 3.9% (CPAC); for RVEDV it was 11.6 +/- 4.8% (FRPAC) and 8.54 +/- 3.2 (CPAC). Mean difference (bias) was 0.06 +/- 0.39 l/min for CO measured with both methods, 19 +/- 35 ml for RVEDV and -3.3 +/- 6.5% for RVEF. CO(CPAC) displayed a strong correlation to CO(FRPAC) (R = 0.97, p = 0.001) as well as RVEF (R for RVEF(CPAC) versus RVEF(FRPAC) = 0.90, p = 0.001). R for RVEDV(CPAC) versus RVEDV(FRPAC) was 0.67, p = 0.001. We conclude that this animal study demonstrates good agreement between RVEF and RVEDV obtained with catheters equipped with a fast response thermistor or with a conventional slow response thermistor allowing accurate monitoring of right ventricular function with a conventional pulmonary artery catheter.

Algorithms↗
PubMed1994

[Electronic picture and data storage and processing with PC in trauma surgery--an anachronism?].

Acquisition, storage and processing of any images relevant in trauma surgery together or in combination with (alpha) numeric data nowadays are possible employing a personal computer. The computing speed that is achieved with 486 cpu's "inside" is sufficient to process images in motion as well as single images to be filtered. The display and process-resolutions required for processing of X-ray-images can be achieved with the PC's hardware as well as with the software available. That is why there is no need any longer for special configurations for X-ray-departments. Calculating the price of the process-environment proposed, about 25,000 DM should be enough including the video tape recorders and the CD-ROM-recorder that are required.

Computer Peripherals↗
PubMed1998

Lifelong administration of high doses of ibandronate increases bone mass and maintains bone quality of lumbar vertebrae in rats.

As part of a long-term safety study the bisphosphonate ibandronate was investigated for its effects on bone quality in lumbar vertebrae in rats. Bone area, bone density and mechanical properties were assessed by peripheral quantitative computed tomography (pQCT), dual-energy X-ray absorptiometry (DXA) and compression tests. Female and male groups of Wistar rats received either vehicle or 3, 7 or 15 mg/kg per day of ibandronate over 104 weeks orally by gavage. Compared with the control group, bone mineral density, compressive strength and stiffness were significantly higher in ibandronate-treated animals, whereas no changes occurred in strain or modulus of elasticity. The increase in vertebral body stress was significant in some of the ibandronate-treated groups. The changes in mechanical properties appear to be due mainly to an increase in bone mass. A highly significant correlation was found between bone mineral density measured either by DXA (r = 0.86) or pQCT (r = 0.85) and maximal strength in vertebral bodies (p < 0.0001 each). In conclusion, we demonstrated that lifelong administration of doses of ibandronate far in excess of any therapeutically intended dose not only increases bone mass and apparent density, but also maintains or even slightly improves bone quality. Bone mineral density measured either by pQCT or DXA can be used as a predictor for ultimate strength in rat lumbar vertebral bodies after treatment with ibandronate.

Animals↗
PubMed2000

Computed radiography printing problems: a quantitative, observer-independent solution.

Even though facilities using computed radiography (CR) operate in an electronic environment, the production of hard-copy films is still necessary during the transition period, as well as for particular needs following complete implementation. We have implemented a quantitative technique to match the response of printed CR film with that of previous screen/film combinations. A stepwedge is radiographed using the conventional system. The same stepwedge is then radiographed (same geometry and technique) using the CR system. Following processing and printing, the plot of optical density versus step for the CR system is compared with that of the screen/film system. Adjustments are made to the printing parameters until the response curves are identical. All other translation tables in the system are set to be linear. This has proven to be a valuable technique for us and provides CR printed image quality that is equivalent to that of our previous screen/film combinations.

Computer Peripherals↗
PubMed1992

Quality monitoring of soft-copy displays for medical radiography.

As presentation of medical radiographic images on soft-copy displays (cathode ray tubes) becomes increasingly prevalent in electronic radiography, methods of quality assurance must be developed to ensure that radiologists can effectively transfer film-based reading skills. Luminance measurements provide the basis for evaluating the state of soft-copy displays. An integrated approach has been implemented at Mallinckrodt Institute of Radiology (MIR, Washington University, St Louis, MO) that facilitates measurement of geographically distributed soft-copy displays with centralized data logging, performance tracking, and calibration. MIR's central radiology image manager exercises the display station that drives the monitor, harvests the measurement data, stores the results, and submits the resulting data for additional processing. The luminance measurements are collected by a small, portable, photometric instrument designed at MIR that includes a serial port that is accessed via local area terminal service supported by the radiology image manager. The design details of the photometric instrument and example luminance characteristics of several soft-copy displays used at MIR are presented in this report.

Computer Peripherals↗
PubMed1998

Comparison of total and regional body composition in adolescent patients with anorexia nervosa and pair-matched controls.

Body composition in 31 adolescent girls suffering from anorexia nervosa (AN) was measured at the time of hospitalization in order to assess the muscle/bone relationship as a potential source of the development of osteopenia. Differences in lean tissue, fat and bone mass in total body, weight bearing and non weight bearing limbs were estimated in AN and pair-matched controls aged 14.2 +/- 1.8 years (range: 9-17 years). Further, it was investigated if bone mineral density (BMD) better reflects the muscle/bone relationship than bone mineral content (BMC). At the distal radius parameters measured by peripheral quantitative computed tomography (pQCT) were used to estimate the association of volumetric bone density to bone strength and lean body mass. The correspondence to the same and different body regions was assessed. Total lean mass in the controls was closely related to total body bone mineral content (TBBMC), as was lean tissue and bone mass of the limb subregions (r = 0.82 to 0.93). In contrast, the correlation was significantly lower in AN (r = 0.33 to 0.77). In the controls, the pQCT-derived bone strength was correlated with muscle mass of the forearm (r = 0.78, p < 0.001), but only moderately in AN (r = 0.47, n.s.). Regional lean tissue was 11-20% and fat mass was 56-66% lower in AN (p < 0.01). After adjustment for height, TBBMC was different at p = 0.01. Within the limbs subregions, BMC (but not BMD) was different in both groups only in the upper arm and the thigh. BMC reflected the bone/muscle relationship better than BMD. Intra- and between group regressions gave no significant differences between weight bearing and non weight bearing limbs. In conclusion, the assessment of musculoskeletal factors may be a useful tool to develop individual preventive measures for therapy after recovery of our patients.

Adolescent↗
PubMed2002

Association of polymorphisms of the estrogen receptor alpha gene with bone mineral density of the femoral neck in elderly Japanese women.

The estrogen receptor alpha gene is a candidate locus for genetic influence on bone mass. The possible association between two polymorphisms in the first intron of this gene, alone or in combination, and bone mineral density at various sites was examined in participants in the National Institute for Longevity Sciences Longitudinal Study of Aging, a population-based prospective cohort study of aging and age-related diseases. The relationship of the TC ( PvuII) and AG ( XbaI) polymorphisms in the first intron of the estrogen receptor alpha gene to bone mineral density was determined in 2230 subjects (1120 men, 1110 women) and in 2238 subjects (1128 men, 1110 women), respectively, all of whom were community-dwelling individuals aged 40-79 years. Bone mineral density at the radius was measured by peripheral quantitative computed tomography and that for the lumbar spine, right femoral neck, right trochanter, right Ward's triangle, and total body was measured by dual-energy X-ray absorptiometry. Estrogen receptor alpha genotypes were determined with an automated fluorescent allele-specific DNA primer assay system. Analysis of the TC ( PvuII) polymorphism revealed that bone mineral density for the total body, femoral neck, and trochanter was significantly lower in women aged 60 years or over with the CC genotype than in those with the TT genotype, but statistical significance was not achieved after adjustment for age, body mass index, and smoking status. Analysis of the AG ( XbaI) polymorphism revealed that bone mineral density for the femoral neck was significantly lower in women aged 60 years or over with the GG genotype than in those with the AA genotype. After adjustment for age, body mass index, and smoking status, bone mineral density for the femoral neck was significantly lower in women aged 60 years or over with the GG genotype than in those with the AA or AG genotypes. Analysis of combined genotypes in women aged 60 years or over revealed that bone mineral density for the femoral neck was significantly lower in women with the CC/ GG genotype than in those with the TT/ AA or TC/ AA genotypes. After adjustment for age, body mass index, and smoking status, bone mineral density for the femoral neck was significantly lower in women aged 60 years or over with the CC/ GG genotype than in those with other genotypes. No differences in bone mineral density at the various sites were detected among TC ( PvuII), AG ( XbaI), or combined genotypes in women aged under 60 years or in men. These results suggest that the estrogen receptor alpha gene is a susceptibility locus for bone mass, especially for the femoral neck, in elderly Japanese women.

Absorptiometry, Photon↗
PubMed2002

[Soft copy versus hard copy findings in digital mammography].

The advantages of full field digital mammography are the excellent and reliable image quality and the reduction of radiation exposure. Image acquisition and display are decoupled in digital mammography allowing for optimization of both independently. Image displays are currently either hardcopy produced with a laser printer or softcopy using a computer monitor. Since the amount of data is high the hardware and software must meet specific technical specifications. The diagnostic accuracy of softcopy and hardcopy interpretation is comparable if a high resolution laser printer and a high quality workstation with high spatial and contrast resolution monitors are used. However, using film display the potential benefits of digital mammography in terms of manipulation of the data is lost. Additional diagnostic benefits might be gained by the combination of softcopy display and computer assisted diagnosis (CAD) and telemammography.

Breast Neoplasms↗
PubMed1999

[Filmless magnetic resonance tomography. Advantages and disadvantages in comparison with film reports].

At our hospital, an average MRI examination comprises 170 images. These examinations were evaluated exclusively on digital reporting systems with two high-resolution monitors for a period of 1 year. A retrospective analysis of this reporting method in comparison with films on a conventional viewing wall was performed with subjective and objective data. Radiologists and technicians were requested to evaluate the system on a subjective scale from 1 to 5 for seven topics (image analysis, inspection, time for reporting, handling, comparison with previous reports, quality of PC laser prints, training period). Moreover, personal interviews were conducted and protocols taken. Patient and image frequency, film costs, data transfer time and amount of system failures were evaluated as objective data. The most important results were: Two thirds of the film checking radiologists prefer the conventional viewing walls over the computer monitors. However, 70% of the residents prefer using the computer monitor for reporting. Seventy percent of the interviewed radiologists considered comparison with former examinations on film very difficult. Digitizing of former MRI examinations was not a convincing method; printing on a standard PC laser printer was considered to yield insufficient quality. The different acceptance between radiologists and residents seems to be related to different experiences. The reduction in film costs (48.6%) will improve further with complete PACS installation in the whole hospital. Data transfer rates are still poor; further improvement of network performance is necessary for convenient work. One whole MRI examination and report could be stored on CD-ROM for a cost of less than 2 euros. This could be a future means of cheap archiving and documentation suitable for viewing on any PC with DICOM III viewer. Images and reports could stay with the patients as in the past.

Computer Peripherals↗
PubMed2003

Aging bone in men and women: beyond changes in bone mineral density.

Using peripheral quantitative computed tomography (pQCT) we assessed trabecular and cortical bone density, mass and geometric distribution at the tibia level in 512 men and 693 women, age range 20-102 years, randomly selected from the population living in the Chianti area, Tuscany, Italy. Total, trabecular and cortical bone density decreased linearly with age ( p<0.0001 in both sexes), and the slope of age-associated decline was steeper in women than in men. In men, the cortical bone area was similar in different age groups, while in women older than 60 years it was significantly smaller by approximately 1% per year. The total cross-sectional area of the bone became progressively wider with age, but the magnitude of the age-associated increment was significantly higher in men than in women ( p<0.001). The minimum moment of inertia, an index of mechanical resistance to bending, remained stable with age in men, while it was significantly lower in older compared with younger women (0.5% per year). The increase in bone cross-sectional area in aging men may contribute to the maintenance of adequate bone mechanical competence in the face of declining bone density. In women this compensatory mechanism appears to be less efficient and, accordingly, the bone mechanical competence declines with age. The geometric adaptation of increasing cross-sectional bone size is an important component in the assessment of bone mechanical resistance which is completely overlooked, and potentially misinterpreted, by traditional planar densitometry.

Adult↗
PubMed2003

Preferential reductions of paraarticular trabecular bone component in ultradistal radius and of calcaneus ultrasonography in early-stage rheumatoid arthritis.

Rheumatoid arthritis (RA) is a major cause of secondary osteoporosis and is frequently associated with both paraarticular and generalized osteoporosis. The present study was designed to investigate the preferential sites of reduction of bone mineral density (BMD), in the early stage of RA, with special emphasis on the differential effect of RA on BMD in trabecular and cortical components. The participants (30 RA patients and 26 healthy participants) were all female with disease duration of less than 1 year. BMD in the radius was measured at 4% (ultradistal site) and 20% (midshaft) to the ulnar length proximal to the end of radius by peripheral quantitative computed tomography. BMD in lumbar spine was measured by dual X-ray absorptiometry and the osteo-sono assessment index (OSI) of the calcaneus by ultrasound. RA patients showed lower BMD preferentially in the trabecular component, but not in cortical bone component of the ultradistal radius than age-matched normal controls. Calcaneus OSI was also significantly reduced. The radial midshaft and lumbar spine did not differ significantly between RA patients and normal controls. Trabecular BMD in the ultradistal radius exhibited negative correlations with serum CRP, ESR, and RF, and calcaneus OSI with M-HAQ score. In conclusion, it was suggested that disease activity of RA and impairment of daily physical activity might be a significant determinant of deterioration of bone structure in paraartciular distal radius and calcaneus, respectively, in early-stage RA patients.

Activities of Daily Living↗
PubMed2003

Which bone densitometry and which skeletal site are clinically useful for monitoring bone mass?

Long-term precision, as well as reproducibility, is important for monitoring bone mineral density (BMD) alteration in response to aging or therapy. In order to investigate which bone densitometry and which skeletal site are clinically useful for monitoring bone mass, we examined the standardized long-term precision of several bone density measurements in 83 healthy Japanese women. Annual BMD measurements were performed for 5 or 6 years using dual X-ray absorptiometry (DXA) on the lumbar spine, radius (EXP5000) and calcaneus (HeelScan); peripheral quantitative computed tomography (pQCT) on the radius (Densiscan1000); and quantitative ultrasound (QUS) on the calcaneus (Achilles+). The long-term precision error for the individual subject was given by the standard error of estimate (SEE), and the standardized long-term precision was defined as the percentage coefficient of variation (CV%) divided by the percentage ratio of the annual bone-loss rate. Based on the CV% of spinal DXA, speed of sound (SOS) and diaphyseal pQCT showed significantly higher precision than others, while radial ultradistal (UD) DXA and heel DXA showed significantly lower precision. The long-term precision errors of other measurements were statistically the same as that of the spinal DXA. The spinal DXA, the radial DXA, and pQCT at both the distal metaphysis and diaphysis showed high rates of annual bone loss. The radial trabecular BMD (pQCT) was significantly higher than that of spinal DXA. The annual rates of bone loss of QUS and of heel DXA were significantly lower than that of spinal DXA. Taken together, standardized long-term precision was obtained in the spinal DXA and radial pQCT. In conclusion, spinal DXA and radial pQCT were considered the most useful monitoring method for osteoporosis, while QUS was considered less useful.

Absorptiometry, Photon↗