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Topological analysis of the three-dimensional structure of the human renal glomerulus using a computer-aided reconstruction system.

A quantitative topological analysis of human renal glomerular capillaries reconstructed from serial sections was performed with the aid of a computer system. The peripheral portions of five glomeruli from each of the subcapsular, midcortical, and juxtamedullary zones were reconstructed, each portion corresponding to about one-sixth the diameter of a glomerulus. Statistically, there was no significant difference in the cycle rank (number of independent cycles) of the glomerular capillary network per unit volume of glomerular capillaries or Bowman's capsule among the three renal zones. It was proved that, irrespective of the location of the glomerulus, the glomerular capillary network possessed a larger cycle rank as the volume of the glomerular capillaries or Bowman's capsule increased. This finding strongly suggests that the mean cycle rank per single glomerulus is largest in the juxtamedullary zone.

Capillaries

[Experiences with a cardiorecorder system for continuous 24-hour registration of heart rate].

Studies regarding to the continuous registration of the heart frequency by a transportable instrument, which can store the data of the heart frequency per minute up to 24h, are presented. It is a tape recorder the speed of which is geared down. Thus a normal tape cassette C 60 is sufficient for a registration of the heart frequency during 2 X 24h. The R-wave of the ECG is registered on the first channel of the tape as a biological signal. Moreover every minute an impulse of a clock is recorded on the second channel of the tape. With help of a second instrument the play back procedure for the 24-h-recording can be performed in about 15 min. The signals of both channels of the tape are transformed in digital rectangle impulses by an installed impulse-converter. The serial impulses are counted per minute with help of the time-mark by an interface in a counter. These data are at disposal in BCD-code. They can be passed on the following peripherals: digital printer, computer, pen-recorder and so on. A parallel standardized recording of the physical activity observed by the subject or by an experimenter allows a statistical evaluation and comparison of the physical activity with the corresponding heart frequency data. Some examples of the aread of occupational health, epidemiology and exercise physiology are discussed.

Electrocardiography

Nucleotide sequence of the pldB gene and characteristics of deduced amino acid sequence of lysophospholipase L2 in Escherichia coli.

The nucleotide sequence of the pldB gene of Escherichia coli K-12, which codes for lysophospholipase L2 located in the inner membrane, was determined. The deduced amino acid sequence of lysophospholipase L2 contains 340 amino acid residues, resulting in a protein with a molecular weight of 38,934. It is characterized by a high content of arginine residues (36 out of 340 residues). The amino acid sequence near the NH2-terminus of the protein is composed of a large number of polar or charged amino acid residues, suggesting that this region cannot be a signal peptide. The hydropathy profile of the deduced amino acid sequence of lysophospholipase L2 was studied. Most of the region was rather hydrophilic, and there was no stretch of hydrophobic amino acid region, such as might be predicted to traverse the lipid bilayer. These results are consistent with the experimental observation that lysophospholipase L2 is extracted by salt solution from the membrane fraction, and it may be classified as a peripheral membrane protein. Computer analysis showed that there is no homology in amino acid sequences between lysophospholipase L2 and other extracellular phospholipases, as well as detergent-resistant phospholipase A, which is another membrane-bound phospholipase in E. coli and whose DNA sequence was determined (Homma, H., Kobayashi, T., Chiba, N., Karasawa, K., Mizushima, H., Kudo, I., Inoue, K., Ideka, H., Sekiguchi, M., & Nojima, S. (1984) J. Biochem. 96, 1655-1664). This is the first report of the primary structure of a lysophospholipase.

Amino Acid Sequence

Contrast medium-induced adverse reactions: economic outcome.

Because the cost of managing an expected greater number of adverse reactions when high-osmolality contrast media (HOM) are used could offset the higher material cost of low-osmolality contrast media (LOM), a prospective study was done of 795 inpatients undergoing any of four procedures involving intravascular injection of HOM: cardiac catheterization, peripheral angiography, head computed tomography (CT), or body CT. The resources used in managing HOM-induced adverse reactions were measured, and the costs of these resources were estimated. Four hundred five patients (51%) had adverse reactions. Reactions were grouped into three classes according to their severity. Class 1 (mild) reactions occurred in 358 patients (45%), class 2 (moderate) reactions occurred in 44 patients (6%), and class 3 (severe) reactions occurred in three patients (0.4%). Ninety-nine patients (12%) consumed resources as a result of an adverse reaction. The average cost of these resources per patient undergoing examination was $1.07 to the radiology department, $5.83 to the hospital, and $12.93 to a charge-paying insurer. Mean (+/- standard deviation) cost to the hospital for managing class 1, class 2, and class 3 reactions were $2.52 +/- $5.33, $24 +/- $54, and $910 +/- $749, respectively. By comparison, the difference in material cost of HOM versus LOM ranged from $93 for body CT to $179 for cardiac catheterization. Even if LOM were to induce no adverse reactions, the increased material cost associated with universal substitution of LOM for HOM would be greater than the expected cost of managing adverse reactions when HOM are used.

Adult

[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

[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

[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

[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

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

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

[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

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

[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

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

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

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