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At least 289 records · Page 16Linked to original sources
PubMedDate not supplied

Computer-assisted stereology: point fraction of lung parenchyma and alveolar surface density in fetal and newborn sheep.

The aim of this study was to determine the accuracy of a new computer-assisted stereological technique in obtaining structural information of the lung. We compared the point fraction of lung parenchyma (Pp) and alveolar surface density (Sv) obtained by established manual point/intercept counting methods and compared them with those obtained using a computer-assisted method. Lung tissues obtained from normally grown fetal sheep (n = 6) and from newborn lambs with severe lung hypoplasia (n = 5) were inflation fixed via the trachea and processed for light microscopy. In verification-of-technique experiments, Pp and Sv correlated well with known values. There was a significant linear correlation between manual and computer-assisted stereological measurements for values of Pp (r2 = 0.92) and Sv (r2 = 0.98). Our data lead us to believe that the computer-assisted stereological technique described in this study provides accurate estimates of Pp and Sv and hence may be a valuable tool for evaluating the effects of factors upon structural development of the lung.

Animals↗
PubMed1993

Novel method for stereo imaging in light microscopy at high magnifications.

A new method for realizing direct stereoscopic (3D) views of thick microscopic sections employs multiple oblique illuminating beams and a single objective lens. Excellent 3D images are obtained in the higher magnification range, where conventional stereo microscopes no longer function. Using conventional microscope optics, significant increases in depth of focus and sharpness are demonstrated.

Alzheimer Disease↗
PubMed1981

On stereochronoscopy.

Stereochrono-phenomena (SCP:s), i.e. changes of the surface configuration of the disc with time, are found in various fundus diseases, not only in glaucoma. If SCP:s exist in a glaucoma case, other fundus diseases have to be excluded before the SCP:s can be attributed to glaucoma. If in a case under observation no SCP occurs within an appropriate time interval (say 1 year), then either there is no glaucoma (in a glaucoma-suspect) or the antiglaucomatous therapy applied was efficient (in a case of definite glaucoma). In some cases, different sites on the disc show unrelated apparent movements of surface elements, not only in different directions but also increasing and decreasing with time. The term 'papillary unrest' is suggested for this phenomenon.

Diagnosis, Differential↗
PubMed1994

A prospective study of the migration of two acetabular components. PCA versus RM cups.

Fifty-nine PCA cups and 61 hydroxyapatite-coated RM cups were included in a prospective randomised study with a mean follow up of 5.2 years. Clinical evaluation revealed better results with the RM cup. Radiological criteria of loosening could be applied only with considerable restrictions as different parameters were assessed: progressively loosened beads in PCA cups and faded contour in RM cups. Migration was measured by a computer assisted method (EBRA). PCA cups showed significantly more longitudinal migration 2 years after operation and subsequently. High migration values correlated with a limp. Loosening as defined by migration was of clinical relevance, could be measured early and predicted the survival rate.

Activities of Daily Living↗
PubMed1994

Stability of the elevated fragment in tibial plateau fractures. A radiographic stereophotogrammetric study of postoperative healing.

Five cases of fracture of the lateral tibial condyle of the split-depression type were treated by elevation of the depressed fragment, bone grafting and cancellous bone screws. During the operation, tantalum markers were inserted into the depressed fragment and the tibial metaphysis for radiographic stereophotogrammetric analysis. Postoperatively a plaster cast was applied for one month and weightbearing was not allowed for 3 months. In three cases, a depression of the elevated fragment, at the most 2.8 mm, recurred during the first month after operation. This was not considered to be significant and more aggressive postoperative mobilisation may be warranted.

Adult↗
PubMed1984

Structure of the parathyroid glands, as revealed by different methods of fixation. A quantitative light- and electron-microscopic study in untreated Mongolian gerbils.

Stereology and semi-automatic image analysis were used with the aim of comparing the structure of parathyroid glands from untreated adult Mongolian gerbils fixed by immersion with those fixed by perfusion. Subclassification of the chief cells based upon the staining affinity or electron density of the cytoplasm was readily performed only in glands fixed by immersion, and so-called atrophic cells were observed only in these glands. The atrophic cells were often surrounded by "light" chief cells. In glands fixed by perfusion, "light" chief cells were only rarely encountered. A significant difference between glands fixed by immersion and those fixed by perfusion was found only with regard to the form of cells and nuclei, those fixed by perfusion being more spherical. When comparing individual cells within glands fixed by immersion, "light" chief cells were more spherical and had a significantly larger nuclear and cellular size, and a lower mitochondrial volume density than the "intermediate"/"dark" chief cells. Otherwise there were no significant differences in any of the parameters investigated. These data indicate that occurrence of so-called "light" chief cells and atrophic cells is a result of improper fixation. The results of this study do not favour the concept of a functional cycle with a simultaneous occurrence of active and inactive cells within parathyroid glands.

Animals↗
PubMed1994

Three-dimensional photographic study of cancellous bone in human fourth lumbar vertebral bodies.

In an analysis of the 3D architecture of cancellous bone, two-dimensional techniques are of limited value. A simple technique employing stereophotographs of whole sections of lumbar vertebrate made possible a detailed description of the 3D structure of the normal fourth lumbar vertebral body and its changes with ageing and osteoporosis. Parallax measurements were used to calculate the real lengths of horizontal trabeculae. The bone presented a continuous spectrum of microstructure, from a honeycomb of tubes, to plates and braces and, finally, fragile rods. A distinct pattern was produced in osteoporotic samples by the removal of horizontal and selected vertical trabeculae followed by a thickening of the remaining vertical trabeculae in the peripheral regions. Very long, thin horizontal trabeculae were formed in all three zones (superior, middle and inferior) during this process. The observation of porotic architecture in intact specimens points to the inadequacy of the clinical criterion of the occurrence of a fracture in judging the osteoporotic state.

Adult↗
PubMed1986

Stereophotogrammetry in the evaluation of the treatment of scoliosis.

A previously existing X-ray stereophotogrammetric method which allows the measurement of simultaneous changes in all components of a scoliotic deformity was developed without the use of invasive methods or skeletal markers. In order to evaluate the changes in rotation and lateral deviation of the scoliotic curve following treatment with the Boston brace, this method was applied to 31 patients suffering from idiopathic scoliosis. The derotational effect of the brace averaged 14 degrees (0-38 degrees) in 21 patients remaining after rejection of those whose radiographs were of inadequate quality. The accuracy, however, was not acceptable because of frequent gross errors due to the poor quality of the radiographs. Image interpretation may be improved by a suggested technique of enhancement based upon a computer program for figure restauration and border detection.

Adolescent↗
PubMed1982

The role of moiré photography in evaluating minor scoliotic curves.

Satisfactory correlation has been observed between the radiographic lateral deviation and moiré documented asymmetry of the trunk in scoliotic curves. The advantage of the moiré method is that it is non-invasive and can document what has been observed for later comparison. This screening method decreases the risk of obtaining too many false positive and negative findings. It also increases the possibility of diagnosing scoliosis earlier than with conventional visual methods and, at the same time, decreases the number of radiographs for minor curves in young patients.

Adolescent↗
PubMed1992

The influence of metal backing in unicompartmental tibial component fixation. An in vivo roentgen stereophotogrammetric analysis of micromotion.

The fixation of the tibial component in 36 patients with conventionally cemented unicompartmental knee arthroplasties for femorotibial gonarthrosis was studied using roentgen stereophotogrammetric analysis (RSA). Twenty-four tibial components were all-polyethylene while 12 were metal-backed. The follow-up was for 6 years. Significant migration was detected for all cases but two and ranged from 0.3 mm to 5.4 mm. The greater part of the migration occurred during the first 1-2 years, after which two-thirds of the prostheses remained stable. Seven all-polyethylene components were subjected to a stress examination after 1-2 years and displacement, induced by external forces, was found in all seven. A strong correlation was found between the extension of the radiolucent line and the migration. Otherwise, neither demographic, clinical, nor radiographic data correlated with the RSA results. In this study metal backing did not have any influence on prosthetic fixation as measured by RSA.

Aged↗
PubMed1979

Instability and wear of total hip prostheses determined with roentgen stereophotogrammetry.

A roentgen stereophotogrammetric analysis of hip prostheses was made in four patients with rheumatoid arthritis during a postoperative period of 2 years. Implanted tantalum balls, prosthetic femoral head, and ends of the wire in the acetabular socket were used as measurement points. The migration of the prosthetic head and the acetabular socket in relation to the pelvic bone was determined. The difference between the cranial migration of the head and the socket is a measure of the postoperative instability of the hip joint and deformation of the prosthetic components. This deformation occurs in the plastic acetabular socket and is mainly due to wear. The roentgen stereophotogrammetric method can be applied to standard hip orostheses with a metal femoral head and a plastic or metal acetabular socket to study migration or loosening of the prosthesis in relation to the supporting bone, prosthesis instability, and deformation of the prosthetic components.

Adult↗
PubMed1981

Roentgen stereophotogrammetry in high tibial osteotomy for gonarthrosis.

In three cases operated with high tibial osteotomy for medial gonarthrosis the exact method of roentgen stereophotogrammetry with tantalum balls as bone markers (Selvik 1974) was used to study angular and translational movement in three dimensions at the operation and during the healing period. Tibial osteotomy caused angular and translational movements even in planes where correction was not intended, and the stereo technique revealed that stability was not present when knee mobilisation started. Correlation between the stereo values and conventional radiographic measurements were best in the frontal plane (root mean square value of discrepancies 1.3 degrees). Roentgen stereophotogrammetry gives superior information compared with the conventional radiographic technique, but it is concluded that the latter has sufficient accuracy for the clinical assessment of corrections in the frontal plane.

Aged↗
PubMed1977

Rapid detection of changes in the optic disc: stereo-chronoscopy.

Easy detection of temporal variations of tissue configurations within the optic disc or other structures is possible by means of stereoscopy: Stereochronoscopy. Photographic pictures of the papilla are taken from time to time at exactly the same angle; when any two of them are paired and viewed with a stereoscope, temporal form changes immediately show up as stereo effects (Schirmer [2]). Since continuing glaucomatous damage cannot be diagnosed either by visual field defects or by actual c/d ratios but only by their temporal changes, this method may prove of diagnostic value.

Adult↗
PubMed1987

Micromotion of conventionally cemented all-polyethylene tibial components in total knee replacements. A roentgen stereophotogrammetric analysis of migration and inducible displacement.

Micromotion of the tibial component in 27 knee arthroplasties for gonarthrosis, three of which were regarded as failures for reasons other than mechanical loosening, was studied using high-resolution roentgen stereophotogrammetric analysis (RSA). Migration over time was found in all cases, ranging from 0.2 to 2.1 mm. The majority of the cases showed migration during the first year only, while a minority migrated continuously during the period studied. The latter group showed more migration even after 1 year. All cases showed inducible displacement in response to external forces, ranging from 0.2 to 1.0 mm. The micromotion correlated with the age of the patient but not with other demographic parameters. Alignment or component position did not correlate with the micromotion. All cases but one had developed a radiolucent zone, and it was concluded that the micromotion occurred in the soft tissue interface between bone and cement. Such micromotion is a normal finding in cemented tibial components in knee arthroplasty.

Aged↗
PubMedDate not supplied

Practical classification of chin deformities.

A visually pleasing chin is an important component of facial harmony. This study was undertaken to introduce a practical classification of chin dysmorphology, which can be used to guide the surgeon toward the appropriate surgical approach to chin repair. Analysis of life-size photography, based on standard anthropometric measurements, was completed on 2,879 patients from 1981 to 1991. Six hundred eighty-four patients were noted to have normal occlusion with some form of chin deformity. Analysis of this group of patients identified seven categories of chin dysmorphism: Class I, macrogenia (n = 170, 24.9%); Class II, microgenia (n = 435, 63.6%); Class III, combination of macrogenia in one direction and microgenia in the other direction (n = 54, 7.9%); Class IV, asymmetry (n = 4, 0.6%); Class V, soft tissue ptosis ("witch's chin") (n = 13, 1.9%); Class VI, pseudomacrogenia (normal skeletal symphysis menti with excess soft tissue covering) (n = 5, 0.73%); and Class VII, pseudomicrogenia (long-face deformity producing clockwise rotation of the normal mandible) (n = 3, 0.4%). Having diagnosed the dysmorphism, logical surgical recommendations for lower face improvement were postulated. Only patients with Class II chin deformity can be corrected with augmentation. Classes I, III, and IV require an osteotomy of the chin. Classes V and VI benefit from soft tissue correction. Class VII deformity can be corrected with a maxillary osteotomy.

Adolescent↗
PubMed1979

Moiré topography--a method for school screening of scoliosis.

The moiré method is tested in school screening of scoliosis. Moiré topography registers a three-dimensional description of the shape of the back. In the straight spine, the moiré shadow pattern is equal on both halves of the back. In structural scoliosis, the moiré pattern differs more with the increasing deformity of the spine. This asymmetry is mainly caused by the rotational component of the scoliosis. These shadow patterns consist of contourlines, which can be compared with those on a relief map. By photographing the moiré shadow lines, the status of the back is documented. In 212 cases, the moiré findings are compared with radiograph observations. A statistically significant correlation is found between the moiré asymmetry (rotational component) and the radiograph findings (lateral deviation according to Cobb). The moiré method seems to fulfil the criteria for a screening method--diagnosis of even minor curves, small risk for false negative findings, simple to handle and can document the back in many children in a short time.

Child↗