Biomedical subjects
N Altman
Publications and source records attributed to N Altman.
Cross-validation of cyanogen bromide-peptide ratios to measure the proportion of type II collagen in pepsin digests of equine articular cartilage, meniscus, and cartilage repair tissue.
Collagen type I and type II were purified from equine flexor tendon and articular cartilage, respectively. Equal amounts of these collagens were cleaved with cyanogen bromide, and 11 mixtures containing increasing proportions of type II collagen were separated in seven identical sodium dodecyl sulfate-polyacrylamide gels. The density of bands was measured in wet gels and the peak areas were used to form six ratios of peptide bands that had polynomial relationships with the known proportions of type I and type II collagen in the mixtures. Calibration curves for determining the proportion of type II collagen in the mixtures were constructed using ratios and combinations of ratios of peak areas. Cross-validation was used to identify calibration curves with the smallest squared prediction error or squared average prediction error for all combinations of ratios. Ratios of peak areas of each one of the seven gels were treated, in turn, as the "unknown," and a prediction was carried out using these unknowns and the ratios from the other six gels. Two ratios had the smallest squared average prediction error and calibration curves were computed for these ratios with all seven gels. These curves were used to estimate the proportion of type II collagen in the pepsin-soluble and the pepsin-resistant fractions of articular cartilage inner and outer meniscus, and cartilage repair tissue. Cross-validation enabled selection of the cyanogen bromide-peptide ratios for calibration curves that resulted in the most accurate estimation of the proportion of type II collagen in pepsin digests of tissues.
Annotated bibliography.
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Annotated bibliography.
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The developing cerebral surface. Preliminary report on the patterns of sulcal and gyral maturation--anatomy, ultrasound, and magnetic resonance imaging.
This literature review provides data on the temporal sequence in which gyri, sulci, and fissures first become apparent on anatomic specimens of the developing brain surface. Ultrasonic display of these anatomic features lags behind the initial appearance of the features by a variable interval, greater in early gestation and diminishing in late gestation. MR imaging, especially three-dimensional surface rendering, displays the degree of surface maturation to advantage. Different publications have provided variable estimates of the time course of surface maturation, leading to discordance in the date tabulated. None-the-less, the overall sequence is clear and the surface features are useful in assessing the degree of fetal-neonatal maturity by ultrasonography and by MR imaging.
Annotated bibliography.
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Magnetic resonance applications in cerebral injury.
CT and MR imaging are complementary in the evaluation of cerebral head trauma. CT is still more useful for the initial evaluation of the acutely unstable patient who has a head injury. However, many lesions are identified by MR imaging such as cortical contusions, small subdural hematomas, and diffuse axonal injuries that may not be seen on CT examinations. In addition, MR angiography can play an important role in the diagnostic evaluation of the trauma patient. MR angiography can be clinically useful in delineating vascular abnormalities such as arterial occlusions, arteriovenous fistulae, dissecting aneurysms, and venous sinus occlusion. In pediatric trauma, MR imaging appears to be superior to CT in assessing head injuries, particularly those due to child abuse.
Pain and discomfort associated with film-screen mammography.
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