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At least 217 records · Page 12Linked to original sources
PubMed1994

Anatomy of membranous bronchioles in normal, senile and emphysematous human lungs.

Serial reconstructions of the membranous bronchioles (MB) were performed in randomly selected tissue blocks cut parallel to the pleural surface in fixated human lungs. Two to four normal, senile, and emphysematous lungs were examined. Three (2 in senile lungs) orders of MB were observed with a dichotomous branching pattern. Emphysematous lungs are characterized by an overall decrease in airway diameter with localized stenoses. Comparison with mean airway diameter (d) and density [n (no. of MBs per cm2 of lung tissue)] of MBs obtained using standard morphometric techniques (random sections approximately 1 cm from the pleura) showed that the values of d and n are biased because of the inclusion in the measurements of a number of respiratory bronchioles and bronchi. When these misclassifications are corrected for, it appears that d corresponds quite well to the mean diameter of the terminal bronchioles (TB) and n to approximately twice the density of TBs. After correction, n is not significantly reduced in emphysematous lungs (the grossly destroyed areas being excluded) compared with normal lungs. The estimate of the number of TBs obtained from the present data is markedly less than that calculated by Weibel (Morphometry of the Human Lung. Berlin: Springer-Verlag, 1963), which suggests that the number of bronchi was overestimated by Weibel by at least one generation. Finally, values of peripheral airway resistance computed from the present anatomic data correspond quite well to direct measurement performed on the same lungs before fixation (Verbeken et al., J. Appl. Physiol. 72:2343-2353, 1992).

Adult↗
PubMed1994

Changes in proliferating cell nuclear antigen expression in glioblastoma multiforme cells along a stereotactic biopsy trajectory.

Proliferating cell nuclear antigen, an auxiliary protein of deoxyribonucleic acid polymerase-delta, has been shown to be a reliable marker of nuclear deoxyribonucleic acid synthetic activity. We applied a monoclonal antibody to proliferating cell nuclear antigen to a series of serial stereotactic biopsies from patients with glioblastoma multiforme and found the proliferative activity to vary relative to biopsy location within or surrounding the solid tissue component of the tumor. Twenty-seven trajectories in 26 patients were analyzed, each consisting of two to five sequential 10 x 1.5 mm core biopsies (mean = 3). The proliferative index (PI) was greatest in those cells located at the solid tumor-infiltrated parenchyma interface. PI values were significantly lower in those biopsy cores located proximal (within infiltrated parenchyma) and distal (within solid tumor tissue) to the solid tumor-infiltrated parenchyma interface (median PI values, proximal to distal: 0.38, 0.66, 5.45 solid tumor-infiltrated parenchyma interface], 0.39, 0.09%). The mean PI values were significantly lower in neoplastic cells samples from regions of peripheral hypodensity on computed tomographic scans compared with those sampled from contrast-enhancing regions (0.9 and 3.91%, respectively). There was no significant difference in the mean PI values of neoplastic cells sampled from regions of contrast enhancement or central hypodensity (3.91 and 4.31%, respectively).

Biomarkers, Tumor↗
PubMedDate not supplied

[Circulatory and metabolic disturbances in accidental hypothermia (author's transl)].

This work sums up several studies: clinical observation (electrocardiogram, cardiac rhythm, circulatory state), and biology (glycemia, blood oxygenation, acid-base balance) in 24 cases of accidental hypothermia, not related to poisoning by central nervous system depressive agents; haemodynamics in 18 of these cases; pathology of the myocardium in 11 cases; haemodynamics and microscopy of the myocardium in dogs with slowly induced or prolonged hypothermia; finally an electron microscope study in hypothermic rats. Electrocardiographic study and continuous monitoring of cardiac rhythm and tracing show, in addition to well known manifestations (bradycardia, lenghtening of QT, J wave), acute dysrhythmias, particularly circulatory arrests by asystole during or even 72 hours after rewarming. The clinical haemodynamic changes, measurable (cardiac output, mean arterial pressure, central venous pressure), or computable (stroke volume, peripheral resistances) are observed during rewarming. Several haemodynamic developments can be distinguished: --favourable evolution when the initial disturbances (decrease in cardiac output and in stroke volume, increase in peripheral resistances) disappear without any therapeutic support: --haemodynamic developments showing at a certain time evidence of hypovolemia requiring only moderate vascular replacement; --haemodynamic developments showing myocardial damage. In some cases, only hypothermia accounts for these. In circulatory arrests during or after rewarming, these haemodynamic disturbances raise the hypothesis of severe cardiac changes due to hypothermia itself.

Acid-Base Equilibrium↗
PubMed1992

[Epidemiology of osteoporosis].

A representative inquiry (n = 4217) in Zürich revealed that 22% of the female population eats a diet poor in calcium. A connection between calcium-deficient nutrition and other unhealthy lifestyles such as lack of exercise, smoking (> 10 cigarettes/day) and regular alcohol intake (several glasses/day) has been shown by multivariate analysis. Therefore one has to suspect, that every third to fourth woman having several risk factors is at risk at entry in menopause. Primary prevention as a population-oriented strategy is therefore sought by general health-education and prevention of accidents in order to lower risks for fractures. Fractures of the collum femoris alone are on the basis of actual life expectancy in Switzerland responsible for 157,000 hospital days in women and 18,000 in men, corresponding to the annual capacity of an acute-cave hospital with 500 beds. With the aid of a risk-group strategy therefore attempts at secondary prevention are necessary. As a cost-effective screening-test every postmenopausal woman should receive a peripheral quantitative computer-tomography. Women with relatively high bone loss-rates and/or low bone density (insufficient stability) could thus be recognized and offered the benefit of an individualized compliance-promoting protective treatment.

Adult↗
PubMed1991

[A method of studying carbohydrate metabolism].

A new method of studying carbohydrate metabolism is described. It involves glucose injection according to a certain glucose law, followed by measurement of the dynamics of its concentration in the peripheral blood and computation, based on the models suggested, of the quantitative characteristics of metabolism; compartment of glucose distribution, maximum assimilation of glucose from its supply, and so forth. The individual characteristics of carbohydrate metabolism are shown to change within broad ranges (from 0.92 to 0.11 g/min). Materials on the method reproducibility are provided.

Blood Glucose↗
PubMed1986

[X-ray computed tomographic aspects of tumors of the colon with peripheral extramucous development].

The authors report three cases of a palpable abdominal mass without clinical evidence of obstruction. In each case, ultrasound diagnosed a solid tumor. Computer tomography examination measured the density of the tumor and the extension of the disease. In each case, the colonic origin was established owing to surgery. Histological examination of the three cases diagnosed a fibroma of the caecum, an enterogenic cyst of the caecum and a T-lymphosarcoma developed from the wall of the left colon.

Adult↗
PubMed1987

Performance evaluation of density measurements of axial and peripheral bone with x-ray and gamma-ray computed tomography.

We examined sources of error in bone measurements made with computed tomography (CT) using a whole-body scanner (GE 8800) and a peripheral-bone CT scanner (developed at the University of Alberta). We investigated the influence of various factors on trabecular bone density: homogeneity and noise in the image plane, linearity of calibration, body size, effects of cortical bone, and the image analysis procedure. With the GE 8800 scanner, the precision (SD) of measurements of a single vertebra is expected to be +/- 1.65% (noise: +/- 0.22%, calibration: +/- 1.3%, analysis: +/- 1%); the accuracy, excluding consideration of marrow fat, varied between -2.7 and +7.3% (compact-bone thickness: 2-5%, body size: -2.5 - +1.5%, calibration: -0.47 - +0.77%). With the peripheral-bone CT scanner, the total precision error (+/- 0.53%) was dominated by noise, with only a minor contribution from the analysis procedure (+/- 0.04%); accuracy varied between -0.6 and +3.4% (effect of cortical bone: up to 3.0%; changes in size of object: -0.59 - +0.4%). The magnitude of these errors was determined under 'ideal' conditions, mostly through phantom measurements; therefore, the errors represent optimistic lower limits in clinical application. Furthermore, measurements of density of cortical bone were not reliable for bone thicknesses of less than about 4 mm with the GE 8800 scanner and less than about 1.5 mm with the peripheral scanner.

Absorptiometry, Photon↗
PubMed1991

Computed tomography-guided minithoracotomy for the resection of small peripheral pulmonary nodules.

Small peripheral pulmonary nodules ranging in size from 1 mm to 20 mm were excised in 58 patients. Computed tomography was used to mark the skin overlying the nodules to minimize the surgical exposure needed for operative identification. The nodules were 1 cm or less in maximum diameter in 76% of the patients. Twenty-six patients had single nodules and 32 patients had multiple nodules. The preoperative diagnosis was inaccurate in 67% of the patients. In 61% of the patients in whom malignancy was suspected, no tumor was demonstrated. Conversely, of the 20 patients in whom a malignant nodule was excised, the preoperative diagnosis was correct in only 50%. Thirty-one patients required no further treatment apart from their biopsy and 27 required additional intervention. Small peripheral pulmonary nodules require biopsy for diagnosis. When percutaneous needle aspiration biopsy is unsuccessful, or technically difficult, a computed tomography-guided thoracotomy is an effective and minimally invasive surgical alternative.

Adult↗
PubMed1979

[Computer tomography in the diagnosis of aortic aneurysms (author's transl)].

The paper describes the diagnosis of ten thoracic, 20 abdominal and three peripheral arterial aneurysms by computer tomography. This permits a definite diagnosis by a non-invasive method, it defines the extent of the aneurysm and the amount of thrombus in the aneurysm; it permits recognition of a leak and is painless and without risk and can be performed rapidly. Morever, computer tomography provides an accurate control of growth of the aneurysm. In some cases a dissection can be recognised. The use of adequate quantities of intravenous contrast medium prevents any possibility of an incorrect diagnosis. The extent and density of the aneurysms, their lumina, clot and wall thickness, as determined by computer tomography are described. The values are compared with the aortic diameters of patients with normal vessels. The advantages of the method, compared with other procedures, are discussed and its role in the diagnosis of aortic and peripheral arterial aneurysms is described.

Aged↗
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↗
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↗