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At least 1,333 records · Page 74Linked to original sources
PubMed1984

[Exocytosis of cytolytic T-lymphocytes studied by cryofracture and stereophotogrammetry].

Cryofracture, stereophotogrammetry and three-dimensional reconstruction were used to study the membranes of cytolytic T lymphocytes (CTL) and target cells (TC) conjugates. Circular bulges free of intramembrane granules and ring-shaped structures, analogous to the sites of vacuole release in secretory cells, appear on the surface of the lymphocyte plasmalemma after 30 to 60 minutes of interaction with TC. Polymorphic vacuoles 70 to 140 nm in diameter are observable in the contact space between lymphocytes and TC. Part of the vacuoles are found on the surface or near the CTL plasmalemma. The data confirm an assumption about the secretory mechanism of the cytolytic effect of T killers.

Animals↗
PubMed1984

Effect of tissue fit on corneal shape after transplantation.

Postkeratoplasty astigmatism is now a major problem preventing visual recovery. Certain postoperative topographic characteristics are felt to be dictated by the fit of the donor corneal button in its recipient bed. Deficient tissue at the wound is predicted to contribute to the location of the steep meridian and excess tissue to the location of the flat meridian. In an eight-cat sample using our Fit Assessment Method and Photogrammetric Index Method, the authors tested the relationship between button fit in recipient bed and resulting corneal curvature at approximately 42, 161, and 289 postoperative days. Corneal symmetry improved between the first and second postoperative periods. Deficient tissue led to steepened curvature and ample tissue to flattened curvature in the first measurement period. When buttons fit poorly, deficient tissue led to steepness in the first postoperative period, but led to flattened curvature 90 deg away from the deficient tissue meridian in the second and third periods. The relationship between ample tissue and flattest postoperative curvature did not depend on the magnitude of button-fed disparity in any period. Corneal elasticity appeared to influence the way tissue disparity affected postoperative topography. Our findings support Troutman's balloon mode. When there was a large amount of uncompensated tissue disparity, the tissue deficiency exerted a force that shortened the translimbal chord. This produced both steepened curvature parallel to this chord soon after surgery and flattened curvature at 90 deg to the chord in the stable postoperative cornea.

Animals↗
PubMedDate not supplied

Moiré fringe topography of the human body.

Moiré fringe topography is introduced as a technique for the quantification of musculoskeletal diseases. The apparatus described includes a glass grid, Polaroid camera, and a 1000-W light source. With accurately positioned subjects, this technique has application in the evaluation of scoliosis, lumbar spine disease, and tumor evaluation . By optimizing the optical principles, computer analysis is allowed, which offers further quantification of contour changes associated with these disease states.

Back Pain↗
PubMed1978

Scoliosis angle. Conceptual basis and proposed definition.

The most commonly used methods of assessing the scoliotic deviation measure angles that are not clearly defined in relation to the anatomy of the patient. In order to give an anatomic basis for such measurements it is proposed to define the scoliotic deviation as the deviation the vertebral column makes with the sagittal plane. Both the Copp and the Ferguson angles may be based on this definition. The present methods of measurement are then attempts to measure these angles. If the plane of these angles is parallel to the film, the measurement will be correct. Errors in the measurements may be incurred by the projection. A hypothetical projection, called a 'rectified orthogonal projection', is presented, which correctly represents all scoliotic angles in accordance with these principles. It can be constructed in practice with the aid of a computer and by performing measurements on two projections of the vertebral column; a scoliotic curve can be represented independent of the kyphosis and lordosis.

Adolescent↗
PubMedDate not supplied

Femoral prosthesis subsidence in asymptomatic patients. A stereophotogrammetric assessment.

A radiographic stereophotogrammetric technique (SPG) was used to evaluate quantitatively the presence of early femoral prosthesis subsidence after total hip arthroplasty (THA). This paper focuses on the measurement of subsidence in 12 patients who remained asymptomatic during the first two years after surgery. Only one of these had SPG estimated subsidence in excess of one millimeter at any timepoint. These findings are consistent with the conclusion that early postoperative subsidence is not a common finding among asymptomatic THA patients.

Hip Joint↗
PubMed1984

A simple geometrical method of measuring anterior chamber dimensions.

Equations are described to derive the true anterior chamber dimensions of an eye from a photograph of its optical section. If the surface of the eye is assumed to be spherical, the three-dimensional coordinates of rays emanating from the anterior chamber to a camera can be transformed to two-dimensional coordinates on a plane, which contains rays both inside and outside of the "eye." The actual dimensions of the anterior chamber then were computed on the basis of the ray tracing over the entire corneal surface. The accuracy of the equations was checked using scales prepared from photographs of curvilinear grids inside an artificial anterior chamber. The advantages of this method are that the true anterior chamber dimensions can be measured in an eye of any corneal curvature and with any type of slit-lamp camera. It appears sufficiently accurate and convenient to be used for clinical and animal studies.

Animals↗
PubMed1984

Application of moiré topography to mantle treatment.

We believe moiré topography is a particularly suitable technique for establishing contours on patients receiving mantle treatment. We derive the fundamental moiré equation from a novel, but simple, consideration of moiré phenomena. Our apparatus is designed to give a difference in height of approximately 1.0 cm between successive moiré fringes. Using an inclined plane test object, an accuracy of better than 3 mm is obtained.

Anthropometry↗
PubMed1984

Longitudinal growth rate of the distal tibia and fibula in children.

In 61 children (30 boys and 31 girls), the growth rates in the distal tibia and fibula were recorded by use of a roentgen stereophotogrammetric technique. The average observation time was about one year and seven months. The growth rates were correlated with chronologic and skeletal age. Adjusting for skeletal age did not significantly change the average growth rates or the scattering of the values. The mean growth rate and the remaining growth from about nine years of age in the boys and eight years of age in the girls were calculated for separate age groups. In the distal tibia in the boys and the girls, the average growth rate decreases from a plateau of about 11 and ten years of age, respectively. Decreasing growth rates were found somewhat later in the distal tibia than in the distal fibula in both the boys and the girls. The growth rates were close to zero at about the same time in the distal tibia and fibula in both sexes. In determining the remaining growth, the large biologic variability indicates the importance of serial measurements on the individual patient. The individual growth charts, together with clinical and radiographic estimation of maturity, provide a guideline for treatment of a patient with growth disturbance of the distal tibia and fibula.

Adolescent↗
PubMed1984

Mobility of the pubic symphysis. In vivo measurements with an electromechanic method and a roentgen stereophotogrammetric method.

Mobility of the pubic symphysis can be measured in vivo by two new methods. One is electromechanic (EM), with steel pins inserted into the bone. The other is roentgen stereophotogrammetric analysis (RSA), with tantalum bone markers implanted into the hip bones. With the first method, movements are directly registered with resistive transducers mounted on the pins. With the second method, movements are deduced with kinematic analysis from roentgen stereophotogrammetric measurements of the positions of the bone markers. Both methods have high precision, about 0.1 mm for translations and 0.1 degrees for rotations. The methods were used in two young volunteers, a man and a woman. In provocative tests with identical loading (alternating, active straight-leg raising in the supine position and standing on alternating left or right leg) there was a good correlation between the two methods. The measured values, i.e., translations of up to 2 mm and rotations of up to 3 degrees, form a basis for more comprehensive studies of normal and pathologic mobility of the pubic symphysis.

Adult↗
PubMed1984

School screening for scoliosis. One experience in California using clinical examination and moiré photography.

In 1980 the legislature of the state of California mandated that school screening programs for scoliosis be implemented. This law resulted in variations in methods and efficacy of the programs. One such program using clinical examination and moiré photography was administered to adolescent girls in two secondary schools in Santa Clara County. The findings of 10% of the clinical examinations were ruled to be "positive," 18% on moiré photography alone and 8% on both examinations. The correlation between the two diagnostic procedures was poor (r = .16). Follow-up was done to determine the outcome of the "positive" cases. In all, 25% of the children classified as having scoliosis had no medical follow-up one year from the request by the screening program team. The documented false-positive rate was 15% based on the screening examination. Definitive radiographic evaluation was reported in very few of the positive cases. Our experience shows the weakness of local programs that have no subject follow-up. It is suggested that public education may be a more effective solution than mass school screening mandates.

Adolescent↗
PubMed1984

Changes in tibiofibular relationships due to growth disturbances after ankle fractures in children.

We analyzed the longitudinal growth of the distal tibial and fibular physes and the longitudinal displacement of the distal metaphysis and epiphysis of the fibula relative to the distal metaphysis and epiphysis of the tibia during growth using a roentgenstereophotogrammetric technique in eight children: six with a traumatic growth disturbance in one or both of the distal tibial and distal fibular physes and two with a normal ankle. In the normal ankles the distal fibular metaphysis moved distally in relation to the distal tibial metaphysis and the growth in the distal fibular physis was slower than that in the distal tibial physis. Growth arrest in the distal fibular physis and continued growth in the distal tibial physis resulted in distal displacement of the fibular metaphysis relative to the tibial metaphysis, probably due to traction on the distal ligaments of the fibula or more rapid growth in the proximal fibular physis than in the proximal tibial physis, or both. Valgus deformity of the ankle developed when the growth of the distal tibial physis exceeded the distal sliding of the fibula, as shown by the stereophotogrammetric analyses and orthoroentgenograms. Growth arrest in the distal tibial physis and continued growth in the distal fibular physis resulted in proximal sliding of the fibula, as shown by the roentgenstereophotogrammetric analyses and serial orthoroentgenograms. This mechanism compensated to some extent for the overgrowth of the fibula. Simultaneous growth arrest in both the distal tibial and the distal fibular physis was associated with movement of the distal end of the fibula in a distal direction relative to the tibia, probably due to the more rapid growth in the proximal fibular physis than in the proximal tibial growth plate. Therefore, growth arrest of the distal tibial or fibular physis may result in either proximal or distal sliding of the fibular metaphysis in relation to the tibial metaphysis. Probably growth arrest in the distal fibular physis has a less favorable prognosis than arrest in the distal tibial physis, because after tibial arrest proximal sliding of the fibula may compensate for overgrowth of the fibula better than distal sliding of the fibula can compensate for fibular arrest and overgrowth of the tibia.

Adolescent↗