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At least 235 records · Page 13Linked to original sources
PubMed1981

[A thermodynamic model to predict oxygen consumption and peripheral blood flow of the newborn infant (author's transl)].

The continuous evaluation of the oxygen consumption and peripheral blood flow is technically difficult and practically not feasible in the newborn infant. We attempted to assess these two variables by means of a thermodynamic model, where only a set of geometrical variables and a set of temperatures have to be measured. The body is represented by a central cylinder (head, trunk) and a peripheral cylinder (extremities) and the heat flux therein is described by mathematical formulas. Only steady state conditions are considered. From the heat flux "surface leads to environment" the oxygen consumption and from the heat flux "central cylinder leads to peripheral cylinder" the peripheral blood flow is derived. On the patient only one core temperature (rectum) and two skin temperatures--one on the chest and the other one on the calf--have to be measured. The validity of the model was tested in 17 healthy newborns (body weight 1,100-3,850 g) and 6 diseased newborns (body weight 1,500-3,400 g). Comparing the computed oxygen consumption to values from the literature for a similar group showed good agreement. In 7 newborns the calculated oxygen consumption correlated well (r = 0.88, p less than 0.01) with the directly and synchroneously measured oxygen consumption. Indirect proof that the model also gives a reasonable index for the peripheral blood flow was obtained by relating the computed peripheral blood flow a) to values from the literature for a similar group and b) by demonstrating the dependence of the (calculated) peripheral blood flow on the haematocrit (r = -0.58, p less than 0.01).

Humans↗
PubMed1993

Air bronchogram in differential diagnosis of small peripheral lung cancers on CT image.

The computed tomographic (CT) images of 52 patients of small peripheral lung nodule < 3 cm proved pathologically were reviewed. Air bronchogram (AB) was found in 14 nodules on thin-section CT images, in which well or moderately differentiated small adenocarcinomas were only seen with lipidic growth. Squamous-cell, large-cell carcinomas and small benign lung nodules had no AB sign both on CT image and in pathologic specimens.

Adenocarcinoma↗
PubMed1980

Comparison of vertebral and peripheral mineral losses in disuse osteoporosis in monkeys.

Vertebral mineral loss (measured by computed tomography) was compared to peripheral mineral loss (measured by photon absorptiometry) in immobilized monkeys. Significantly greater loss was found in axial cancallous bone than in peripheral cortical bone. The accuracy of vertebral CT measurements in one animal was determined using direct chemical analysis of excised vertebrae. Results indicate that mineral changes may be detected earlier in the vertebrae by CT than in peripheral bone using photon absorptiometric techniques.

Absorption↗
PubMedDate not supplied

Myxoid intraneural cysts of external popliteal ischiadic nerve. Report of 2 cases studied with ultrasound, computed tomography and magnetic resonance imaging.

Peripheral neuropathy of the external popliteal ischiadic nerve caused by intraneural cysts is a very rare and peculiar pathological phenomenon compared with diseases associated with extraneural cysts or colliquative phenomena of solid nervous lesions. Two cases of peripheral neuropathy of the external popliteal ischiadic nerve caused by intraneural cysts and evaluated with ultrasound, computed tomography and magnetic resonance are described. The diagnostic efficacy of these imaging modalities is also evaluated with particular reference to MR capability to define the morphology of such lesions and their relationships to the surrounding structures. It is not yet possible to obtain a correct diagnosis about histopathologic features by means of the imaging techniques currently available. Nevertheless, they do provide information about the involvement of the neighboring areas, which are useful indications for possible surgical treatment of the disease.

Adult↗
PubMed1986

[Diagnostic imaging of peripheral soft tissue tumors with special reference to computed tomography].

The further development of modern therapeutical procedures in the treatment of soft tissue tumors requires an improvement of radiological diagnostics. The diagnostic values of X-rays, angiography, sonography and computed tomography is estimated critically. The results of own CT examinations in 120 patients with soft tissue tumors and of 50 ultrasound examinations show the importance of these methods in the extent diagnosis of soft tissue tumors. Ultrasound or CT- guided biopsy are helpful to prove the definitive diagnosis. These methods have reduced the use of angiography.

Adolescent↗
PubMed1990

Magnetic resonance imaging simulator: a teaching tool for radiology.

The increasing use of magnetic resonance imaging (MRI) as a clinical modality has put an enormous burden on medical institutions to cost effectively teach MRI scanning techniques to technologists and physicians. Since MRI scanner time is a scarce resource, it would be ideal if the teaching could be effectively performed off-line. In order to meet this goal, the radiology Department at the University of Pennsylvania has designed and developed a Magnetic Resonance Imaging Simulator. The simulator in its current implementation mimics the General Electric Signa (General Electric Magnetic Resonance Imaging System, Milwaukee, WI) scanner's user interface for image acquisition. The design is general enough to be applied to other MRI scanners. One unique feature of the simulator is its incorporation of an image-synthesis module that permits the user to derive images for any arbitrary combination of pulsing parameters for spin-echo, gradient-echo, and inversion recovery pulse sequences. These images are computed in 5 seconds. The development platform chosen is a standard Apple Macintosh II (Apple Computer, Inc, Cupertino, CA) computer with no specialized hardware peripherals. The user interface is implemented in HyperCard (Apple Computer Inc, Cupertino, CA). All other software development including synthesis and display functions are implemented under the Macintosh Programmer's Workshop 'C' environment. The scan parameters, demographics, and images are tracked using an Oracle (Oracle Corp, Redwood Shores, CA) data base. Images are currently stored on magnetic disk but could be stored on optical media with minimal effort.

Computer Simulation↗
PubMed1986

Basic principles of computer technology.

This article explains the functions of the different components of computer systems and how they work together. Covered are computer central processors, various peripheral accessories, and the types of software that control them.

Computers↗
PubMed1987

Evaluation of peripheral vascular disease by intravenous digital subtraction angiography with the Fuji computed radiography (FCR) system.

Intravenous digital subtraction angiography using Fuji computed radiography system (FCR-DSA) was used to evaluate 57 preoperative patients with clinical manifestations of peripheral vascular disease of lower extremity. With its high contrast resolution and good special resolution, image of FCR-DSA could offer optimal information of vascular abnormality in lower extremity distal to midfoot for the diagnosis and the choice of management.

Adult↗
PubMed1990

The use of selective inhibitors and computer modelling to evaluate the role of specific high affinity cyclic AMP phosphodiesterases in the hormonal regulation of hepatocyte intracellular cyclic AMP concentrations.

Using experimentally derived data for the activities and kinetic constants of hepatocyte cyclic AMP phosphodiesterase isoenzymes together with the derived changes in adenylate cyclase activity, due to stimulation and subsequent desensitization by glucagon, a computer model was established to simulate hepatocyte cyclic AMP metabolism. The established ability of glucagon to activate the 'dense-vesicle' cyclic AMP phosphodiesterase by eliciting its cyclic AMP-dependent phosphorylation was shown on the model to be capable of eliciting a profound reduction in the glucagon-stimulated increase in intracellular cyclic AMP. This was consistent with experimentally derived observations using the compound ICI 118233 which was used to inactivate the 'dense-vesicle' enzyme selectively. The non-hydrolysable adenosine agonist N6 (phenylisopropyl)-adenosine (PIA), which prevents glucagon pre-treatment of hepatocytes blocking the ability of insulin to stimulate the peripheral plasma membrane cyclic AMP phosphodiesterase, is shown here to accentuate the ability of insulin to decrease glucagon-elevated intracellular cyclic AMP concentrations. This effect was obliterated using the compound ICI 63197, a selective inhibitor of the peripheral plasma membrane phosphodiesterase. Computer modelling studies, taking into account experimentally derived actions in insulin in activating the peripheral plasma membrane phosphodiesterase, confirmed the potential of this enzyme to decrease intracellular cyclic AMP concentrations. Modelling of the putative effect of an insulin 'mediator' in activating the two cyclic GMP-stimulated cyclic AMP phosphodiesterase isoenzymes was shown to elicit a decrease in intracellular cyclic AMP concentrations which was comparable to that caused by insulin's action on intact hepatocytes. The relative contribution of each phosphodiesterase form to the metabolism of hepatocyte intracellular cyclic AMP, together with an assessment of the potential effect of inhibition and activation of specific species, was evaluated using the computer model. These experimental and stimulation studies indicate that alterations in the phosphodiesterase activity of the 'dense-vesicle' enzyme, the peripheral plasma membrane enzyme, the cyclic GMP-stimulated cyclic AMP isoforms and the IBMX-insensitive PDE-MQ-II can elicit profound effects upon hepatocyte intracellular cyclic AMP concentrations.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1987

Mesencephalic hemorrhage and third nerve palsy.

We report the clinical and computed tomography findings in two patients with small mesencephalic hematomas. Both patients presented with unilateral oculomotor paralysis and minor associated neurological symptoms. One patient had pupillary involvement suggestive of a peripheral third nerve lesion. Computed tomography evaluation disclosed small unilateral anterior mesencephalic hematomas involving the oculomotor fascicle. Angiography in both cases and surgery in the first case disclosed no evidence of an arteriovenous malformation or neoplasm. Both patients showed significant clinical improvement within 3 months.

Adolescent↗
PubMed1982

[Studies of peripheral nerve conduction velocities in vibrating tool operators].

Vibrating tools such as chain-saws, rock-drills, grinders and tie-tampers have been widely used in many kinds of industries in Japan, causing vibration syndrome among the operators. As is well-known, the syndrome includes disorders of the peripheral circulation in the hands, e.g. Raynaud's phenomenon, and of the peripheral and central nervous systems. As the result of preventive countermeasures to the syndrome during the last decade, the picture of the syndrome has been partly changing especially for the patients among the state forestry workers; for example, the prevalence of the peripheral nerve disorders has been relatively increasing compared with that of Raynaud's phenomenon. Peripheral nerve disorders such as numbness, paresthesia and hypesthesia in the upper limbs tend to be usually cumulative and irreversible. The disorders are very important problem of vibration syndrome from the standpoint of treatment and prevention, though there are only a few reports of the study on the disorders using electrophysiological methods. In order to make objectively clear the peripheral nerve disorders, 236 male vibrating tool operators (= Group V) were examined. The following nerve conduction velocities were measured: (1) Maximal motor nerve conduction velocities (MCV) of the median and ulnar nerves in the forearm. (2) Sensory nerve conduction velocities (SCV) of the median and ulnar nerves in the forearm and palm. (3) Residual latency (RL) of the median and ulnar nerves. Besides, working conditions and complaints relevant to vibration syndrome were examined by using questionnaires. MCVs, SCVs and RLs that were outside of mean +/- 2 S.D. of the control group (= Group C), consisting of 30 healthy men, were evaluated as abnormal. The obtained results led to the following conclusions: (1) All MCVs, SCVs and RLs of Group V were significantly less than those of the control group. In Group V, prevalence of the abnormality in each of forearm SCVs was higher than that in each of MCVs of the corresponding nerves. (2) The difference between the median and ulnar SCV in the palm and the respective SCV in the forearm of each subject was significantly greater for Group V than Group C. (Palm-forearm difference) (3) The difference between the forearm and palmar SCV of the ulnar nerve and the respective velocities of the median nerve was statistically greater for Group V than for Group C. (Ulnar-median difference) (4) Ulnar SCV in the palm of Group V was significantly related to the total operating hours of vibrating tools. (5) There was no significant relation between all the nerve conduction velocities and the white finger attack. But a significant relation was noticed between the prevalence of the abnormal values of ulnar SCV in the palm and the peripheral circulatory function score computed from the data of nail press test and cold immersion test.

Adult↗
PubMedDate not supplied

Image feature analysis and computer-aided diagnosis in digital radiography. 3. Automated detection of nodules in peripheral lung fields.

We are investigating the characteristic features of lung nodules and the surrounding normal anatomic background in order to develop an algorithm of computer vision for use as an aid in the detection of nodules in digital chest radiographs. Our technique involves an attempt to eliminate the background anatomic structures in the lung fields by means of a difference image approach. Then, feature-extraction techniques, such as tests for circularity, size, and their variation with threshold level, are applied so that suspected nodules can be isolated. Preliminary results of this automated detection scheme yielded high true-positive rates and low false-positive rates in the peripheral lung regions of the chest. This detection scheme, which can assist the final diagnosis by the clinician, has the potential to improve the early detection of lung carcinomas.

Diagnostic Errors↗
PubMed1976

[Experiences with computer-assisted x-ray diagnosis of pulmonary coin lesions (author's transl)].

Favourable results of the computer-aided diagnosis of peripheral bronchial carcinoma lead to a simplified scheme for calculation fo diagnosis, basing upon X-ray symptoms. This scheme was tested in the Zentralinstitut für Krebsforschung (ZIK) in 102 pateints and in the Forschungsinstitut für Lungenkrankheiten und Tuberkulose (FLT) in 101 patients. These patients had coin lesions of the lung with unknown diagnoses. The histological diagnoses later proved were compared with the calculated diagnoses. In ZIK there were correct diagnosis in 92.16% (in 96.53% of the carcinomas, in 44.4% of the tuberculomas and in all benign tumors), while in FLT 85.53% of the coin lesions were correctly classified (89.13% of carcinomas, 79.31% of the tuberculomas and all benign tumors). The comparison with the clinical-histological diagnoses showed a clear improvement of the accuracy by the calculated diagnoses. The method can be recommended for the basic diagnosis especially of peripheral bronchial carcinoma. It implies a reduction of the diagnostic delay, but it can not substitute the histologic investigation of the lesions.

Adult↗