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 289 records · Page 16Linked to original sources
PubMed1988

Clinical significance of hematic cyst of the orbit.

Hematic cyst is a rarely encountered orbital lesion consisting of encapsulated blood or blood breakdown products. The abnormality may be recognized by identifying the cystic structure by B-scan ultrasonography or computed tomography. Cysts located peripherally in the orbit tend to have histologic features suggesting hematoma formation. More centrally located orbital cysts are sometimes associated with vascular abnormalities. In other cases, the etiology is obscure, as in the case presented here. The visual prognosis is usually good, and associated systemic abnormalities are lacking.

Adult↗
PubMed1993

Direct digital dental x-ray imaging with visualix/VIXA.

Visualix (VIXA in North America) is a new commercial system for direct dental x-ray imaging. It is based on a special charged-coupled device sensor and a personal computer platform with dedicated peripherals. Application software is installed that manages the operation of the sensor and provides a user interface specifically conceived for real time imaging. Given the high sensitivity of the sensor and the corresponding low dosage required, the performance of the system in terms of signal-to-noise ratio is essentially determined and limited by the quantized nature of the original radiologic information in the x-ray beam. At full scale range, the dose requirements are approximately six times less than those for a D-speed film.

Artifacts↗
PubMed1991

Peripheral nerve function in sepsis and multiple organ failure.

Forty-three patients who had sepsis and multiple organ failure (critical illness) were studied prospectively to determine the incidence and severity of peripheral nerve function and to correlate such function with a number of variables. Electrophysiologic studies indicated a primary axonal degeneration of motor and sensory fibers in 30 (70 percent). Fifteen (30 percent) had the clinical signs of difficulty in weaning from assisted ventilation, weakness of limb muscles, and reduced or absent deep tendon reflexes. Full recovery from the polyneuropathy occurred among the 23 (53 percent) who survived, except three who had a very severe polyneuropathy. A peripheral nerve function index, computed from electrophysiologic measurements, showed statistically significant (p less than 0.01) negative correlations with the time in the critical care unit, and the serum glucose value; the serum albumin level showed a positive correlation. Multiple regression analyses indicated all three factors accounted for 47 percent (r2 = 0.4678) of all potential variables. In a separate analysis, the nerve function index correlated with the amplitude of the diaphragm compound muscle action potential (p less than 0.01). The results were consistent with the polyneuropathy being due to the same mechanisms that are currently postulated to cause dysfunction in this syndrome of other organ systems (including the neuromuscular respiratory system).

Bacterial Infections↗
PubMed1986

Changes in systemic vascular resistance detected by the arterial resistometer: preliminary report of a new method tested during percutaneous transluminal coronary angioplasty.

A recently developed apparatus provides on-line continuous monitoring of systemic vascular resistance (SVR) by means of simple computer analysis of the peripheral arterial waveform. The fundamental equation of this method is Ri = P'/(dP/dt), where dP/dt is the peak dP/dt of the peripheral arterial waveform, P' is the pressure at time of peak dP/dt, and Ri is a resistance index that bears a direct relation to SVR. Eleven patients undergoing percutaneous transluminal coronary angioplasty (PTCA) were studied to evaluate the changes in SVR associated with myocardial ischemia (angina detection). There were 49 balloon inflations, all of which were associated with an increase in Ri (from 38.4 +/- 12 to 81.2 +/- 36 X 10(-3) sec; p less than .01) and a decrease in dP/dt (from 2076 +/- 257 to 1327 +/- 326 mm Hg/sec; p less than .01). In 42 of the balloon inflations these changes were associated with electrocardiographic ST-T changes and in 23 it was also associated with anginal pain. When angina was present, a further increase in Ri (to 97.5 +/- 43 X 10(-3) sec; p less than .01) and a decrease in dP/dt (to 1218 +/- 338 mm Hg/sec; p less than .01) was observed. It was found that myocardial ischemia is associated with an increase in the resistance index and a decrease in dP/dt and can be detected by the resistometer.

Angioplasty, Balloon↗
PubMed1987

Beat-to-beat estimation of peripheral resistance and arterial compliance during pressure transients.

We have used a computer-based parameter estimation method to obtain peripheral resistance, total arterial compliance, and characteristic resistance from the measurement of aortic pressure and flow in the open-thorax cat, assuming the three-element windkessel as a model of the systemic arterial tree. The method can be applied on a beat-to-beat basis in the steady state and in transients. We have validated this method by analyzing nonsteady-state data obtained from an electrical analog with fixed values of the resistances and compliance and by showing that the values obtained by this procedure were within 5% of the fixed values of the circuit. Changes in total peripheral resistance and arterial compliance were studied before, during, and after acute heart rate changes in five open-thorax cats with blocked autonomous nervous system. As expected, the peripheral resistance, estimated during the heart rate transient [3.93 +/- 0.94 (SE) kPa X ml-1 X s] was the same as before the transient (3.53 +/- 0.83 kPa X ml-1 X s); total arterial compliances were also identical (0.28 +/- 0.04 vs. 0.27 +/- 0.03 ml/kPa). In six cats without nervous blockade we obtained similar results. Calculation of peripheral resistance during transients from the mean pressure-to-mean flow ratio, i.e., without correction for arterial compliance, suggested changes in resistance values of less than or equal to 57%, which shows that correction is necessary. The findings indicate that peripheral resistance and total arterial compliance can be estimated in vivo on a beat-to-beat basis, even during hemodynamic transients.

Animals↗
PubMed1984

Subpleural pulmonary hamartoma: demonstration by computed tomography.

A case of a subpleural pulmonary hamartoma demonstrated by computed tomography is presented. The literature on subpleural pulmonary lesions demonstrated by computed tomography is reviewed. Although peripheral pulmonary hamartomas have been well documented, we believe this is the first demonstration of a subpleural location by computed tomography scanning. In the appropriate clinical setting, pulmonary hamartoma should be included in the differential diagnosis of subpleural lesions identified on computed tomography scanning of the chest.

Aged↗
PubMed1996

Morphometric analysis of noninvasively assessed bone biopsies: comparison of high-resolution computed tomography and histologic sections.

This article describes a new method to analyze the structural behavior of trabecular bone structure by means of noninvasive measurements of the three-dimensional cancellous bone architecture. For the noninvasive data acquisition, a high-resolution quantitative computed tomography system for peripheral measuring sites (pQCT) was used. With this system and the help of a multiple thin-slice measuring technique, it became possible to examine three-dimensional bone structure with a resolution of 0.25 mm. Using a special three-dimensional segmentation algorithm, mineralized bone was separated from bone marrow and muscle tissue within the three-dimensional stack of CT slices. These segmented data sets can then be processed nondestructively and, even more important, repetitively in either two or three dimensions. In order to validate this noninvasive procedure, a two-dimensional comparative morphometric study was performed including CT slices and corresponding histologic sections prepared after CT measurement. Three representative sections from the three-dimensional stack of CT slices were selected and the morphometric indices of the segmented CT slices were compared with the indices stemming from the corresponding histologic sections prepared after CT measurement. Although the presented approach can only give an example of the method, the results from the morphometric analysis support the assumption that cancellous bone structures based on noninvasive high-resolution CT measurements are representative for trabecular microstructures assessed from histologic bone sections. The study demonstrates the potential of high-resolution CT imaging for in vivo applications of quantitative bone morphometry. This is especially true for repetitive follow-up measurements, which cannot be performed using histologic sections. Additionally, the method offers an easy access to the three-dimensional structure of trabecular bone, which is mandatory for the analyses of the anisotropic mechanical behavior of cancellous bone.

Algorithms↗
PubMed1993

Intrinsic stability of 'self-sealing' unsutured cataract wounds.

Many operative and postoperative factors can influence cataract wound stability and postoperative astigmatism. The final outcome is fundamentally dependent on the intrinsic biomechanical stability of the corneal dome in the presence of the wound. We determined the stability of the central and peripheral cornea with computer-assisted topographic analysis of six freshly enucleated human globes. Self-sealing, unsutured, scleral tunnel wounds 4.0 mm in length were dissected, with widths varying from 1.4 to 6.0 mm. Intraocular pressure was elevated in 5-mm increments from 15 to 40 mm Hg without measurable topographic change in the visual axis or superior cornea. We conclude that these long scleral tunnel wounds do not necessarily destabilize the cornea within the usual range of intraocular pressure. Postoperative-induced astigmatism is therefore due to other operative and postoperative factors. Some of these factors may be identifiable with this model and controlled or eliminated.

Astigmatism↗
PubMed1995

Long-term stability of blood pressure and pressor reactivity to mental stress in borderline hypertension.

Borderline hypertension is characterized by pressor hyperreactivity to mental stress. However, it has not been shown whether blood pressure hyperresponsiveness is a temporary phenomenon due to situational anxiety or a stable feature of the borderline hypertensive state. We therefore evaluated the long-term stability of invasively assessed blood pressure and central hemodynamic responses to mental stress in 10 young male subjects with borderline hypertension recruited from a population screening. Two identical 10-min mental arithmetic stress tests were performed 50 to 62 months apart (median, 4 years 8 months). Intraarterial blood pressure was monitored continuously before, during, and after stress. Cardiac output was measured by the indocyanine green dye dilution technique and indexed for body surface area. Total peripheral resistance index was computed from cardiac index and mean arterial pressure. During the 4-year follow-up period, none of the central hemodynamic parameters had changed significantly, either with respect to rest or stress levels. Test-retest variability of blood pressure measures was low, and errors of measurement ranged between 4.8 and 8.2 mm Hg for blood pressure levels at rest and during stress. Mental arithmetic induced highly significant blood pressure increments on both occasions (ANOVA, P < .0001 throughout). Pressor responses were somewhat but not significantly lower during the second test. Errors of measurement for absolute blood pressure reactivity ranged between 3.9 and 7.1 mm Hg. Intersession correlation coefficients for blood pressure levels attained during stress were above r = 0.75 throughout (P < or = .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Arginine-induced insulin release in glucokinase-deficient subjects.

OBJECTIVE: In eight glucokinase (GCK)-deficient subjects, we have investigated insulin secretion rates (ISRs) in response to intravenous arginine. Impairment in the enzymatic activity of mutant GCK leads to a reduced glycolytic flux in beta-cells. This defect translates in vivo as a right shift in the glucose/SR dose-response curve. Insulin secretion in response to other secretagogues has not been reported. RESEARCH DESIGN AND METHODS: The arginine test was performed immediately after a 2-h hyperglycemic (10 mM) clamp. ISR was computed by deconvolution of peripheral C-peptide levels. Linear regression analyses were performed to assess correlations between the beta-cell secretory responses to the arginine test, an intravenous glucose tolerance test (IVGTT), and a hyperglycemic clamp (areas under the C-peptide curves), and between these parameters and the glucose tolerance status (area under the glucose curve during an oral glucose tolerance test). RESULTS: Two minutes after the injection of arginine, the increment in ISR was 30.17 +/- 10.01 pmol insulin.kg-1.min-1 in patients and 36.25 +/- 15.46 pmol insulin.kg-1.min-1 in control subjects (P = 0.38). Throughout the experiment, increments in ISR were comparable in both groups. The amount of insulin secreted in response to arginine (0-5 min) was similar in patients and control subjects: 81 +/- 28 vs. 119 +/- 55 pmol/kg (P = 0.16), respectively. The arginine test C-peptide response was not correlated with the IVGTT or hyperglycemic clamp responses. The arginine test and hyperglycemic clamp responses were not correlated to the glucose tolerance status. The best predictor of the glucose tolerance was the C-peptide response to the IVGTT (r2 = 0.78; P = 0.002). CONCLUSIONS: beta-cell secretory increment in response to arginine was found to be in the normal range in GCK-deficient subjects. The arginine test does not seem to reflect either the beta-cell secretory defect or the glucose tolerance status of these subjects. IVGTT seems to be the best predictor of the latter parameter in this population.

Adolescent↗
PubMed1986

Rat heart fatty acid-binding protein is highly homologous to the murine adipocyte 422 protein and the P2 protein of peripheral nerve myelin.

The rat heart contains an abundant cytosolic protein which binds long chain fatty acids. We have determined its primary structure by Edman degradation of peptides generated from chymotryptic, tryptic, and elastase digestions. This polypeptide (Mr = 14,992) contains 134 amino acids and has a blocked (acetylated) NH2 terminus. The sequence of rat heart fatty acid-binding protein (FABP) is remarkably similar to the murine adipocyte 422 protein and the P2 protein of peripheral nerve myelin. Computer-assisted alignment of heart FABP and 422 revealed that 82 of 132 comparable residues are identical (62%). There are 77 identities out of 131 possible matches between this protein and the human myelin P2 protein (59%). Similar comparisons demonstrate that heart FABP has significant homology to several other proteins which bind hydrophobic ligands. The rank of order of similarity to heart FABP is: 422 greater than myelin P2 greater than cellular retinoic acid-binding protein greater than cellular retinol-binding protein II greater than cellular retinol-binding protein greater than intestinal FABP greater than liver FABP. These eight sequences form a family of paralogous homologues. Heart FABP has a region of internal homology involving tandemly arrayed oligopeptides spanning residues 71-100 and 101-131. This feature is not found in the 422 and P2 sequences. The endogenous ligands bound by the 422, P2, and heart FABP sequences have not been defined. Interpretation of the biological significance of their structural similarities and differences will require information about their ligand specificities and affinities.

Amino Acid Sequence↗
PubMedDate not supplied

A method for continuous on-line monitoring of systemic vascular resistance (COMS) after open heart procedures.

A new method for continuous on-line measurement (COMS) of systemic vascular resistance (SVR) utilizing simple computer analysis of the peripheral arterial waveform is presented. The fundamental equation of this method is: (Formula: see text) where SVR is systemic vascular resistance, dP/dt is the peak dP/dt of the peripheral arterial waveform, and P' is the pressure at the time of peak dP/dt. F and a are calibration constants determined by taking simultaneous measurements by an independent method (thermodilution) before (low SVR) and immediately after (high SVR) aortocoronary bypass operations. In 22 patients 255 COMS of SVR readings were recorded simultaneously with thermodilution cardiac output measurements. Patients were exposed to situations such as temperature changes, volume load, blood loss, and the effect of drugs such as various catecholamines, nitroglycerin, and nitroprusside. Linear regression analysis was performed to compare the SVR calculated from thermodilution with the COMS-SVR measurements. SVR values ranged from 450 to 4400 dynes/sec/-5 and correlation between COMS and thermodilution was r = 0.98. Correlation coefficients of individual patients ranged from r = 0.9 to r = 0.986. We found COMS SVR measurements accurate, reliable, and extremely helpful in the management of hemodynamically unstable patients.

Adult↗
PubMed1985

[Determination of the ejection fraction of the left ventricle by videodensitometric analysis of digital angiography. Preliminary results].

Digitalisation enables angiocardiography to be performed by a peripheral intravenous injection. Computer-assisted analysis of the date widens the possibilities of quantification. The authors have developed a videodensitometric method of studying the left ventricular ejection fraction. The research was performed on an experimental model and the technique validated in a series of 10 patients. The experimental model consisted of a series of balloons which, when inflated with contrast medium assumed an allipsoid shape resembling a left ventricle. The balloons were blown up in two stages with an automatic injector to simulate systole and diastole. The images were recorded in the same way as during ventriculography. Videodensitometric measurements showed 3 to 5% variations from the true values. The method was then applied to the calculation of the left ventricular ejection fraction in 10 patients: left ventricular function was also quantified by geometrical methods (Dodge) from the same angiogrammes and the 2 sets of results were then compared. The correlation coefficient between the two methods was 0.97, so validating the new technique. Videodensitometry opens up new perspectives in the study of left ventricular function. On the other hand it can be used to monitor the ejection fraction in severely ill or recently operated patients, and, on the other hand the principle of videodensitometry eliminates the geometrical approximations inherent in the classical methods of angiographic analysis and would therefore seem to be more suitable for the study of pathological left ventricules (aneurysm...). Finally, the technique of videodensitometry represents a new step towards the measurement of true volumes and flow rates.

Absorptiometry, Photon↗
PubMed1982

New concepts of ventilation.

A short survey is given of established methods for ventilatory support. The merits of intermittent mandatory ventilation (IMV) and the new mode of mandatory minute ventilation (MMV) are discussed and compared. The importance of gasflowpressure patterns are analyzed as based on measurements on an awake, non-medicated intubated subject. It can be demonstrated that an inspiratory-assist function minimizes the work of breathing associated with increased airway resistance in the peripheral airways. A metabolic computer system for automatic continuous measurements of oxygen uptake and carbon-dioxide elimination during ventilatory care is described. This metabolic computer is designed to be used with the Engström Erica ventilator and makes it possible to evaluate the caloric demand of the patient as well as the effects of various compositions used for parenteral nutrition.

Airway Resistance↗
PubMed1996

[The presence of cesium-137 in the tissue of a lung tumor in someone who cleaned up the aftermath of the accident at the Chernobyl Atomic Electric Power Station].

A man of 66 participated in the emergency works after the Chernobyl accident. His official dose of radiation comprised 24 roentgens. In March, 1993, he underwent prophylactic examination including computed tomography which revealed peripheral tumor in the lower part of the left lung with penetration in the lymph nodes of the lung root. Biopsy showed it to be adenocarcinoma. Moreover, electron-microscopically, more than 40% of alveolar macrophages contained large optically dense particles in the cytoplasm. After lobectomy in March 1993 x-ray and gamma spectrometry of the removed lung tissue recorded high content of 137Cs (0.1-0.18 Bq). This finding evidences possible long-term deposition of radionuclides in the bronchopulmonary system of radiation-exposed subjects.

Adenocarcinoma↗
PubMed1982

A dose table describing fractions of peripheral volume for 125I volume implants.

A dose table that provides the dose as a function of fractions of peripheral volume for 125I implants is presented. The table is based on seed distributions from 50 actual patient implants. Computer dosimetry was used to determine peripheral doses and dose ranges within implant volumes. The effects of seed distribution were also examined. The patient data and a study of computer-generated randomized seed coordinates within a given volume suggest that matched doses do not depend strongly on the exact position of each seed. The table provides the means for planning an implant to obtain a desired peripheral dose that can be directly compared with the postimplant computer dose calculation.

Brachytherapy↗