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The cetacean humerus is a short, robust bone without an open medullary cavity. It lies in the base of the resilient, streamlined pectoral limb (flipper) between the only free articulation (the glenohumeral) and approximately the body contour. The humerus is acted upon by muscles of the shoulder complex and receives loadings from the flattened distal portion of the limb as this hydroplane acts against body inertia and water resistance in control of body attitude. This study is an analysis of development and structure of the humerus in terms of the unique functional role of the flipper of finback, beluga and pilot whales. Gross external and internal architecture are depictued by photographs and by whole bone and frontal section radiographs. Structural density (bone/unit volume of humerus, with mineral content known to be constant) is analyzed indirectly by photodensitometry of standardized radiographs of sawed sections. Results are shown in graphic reconstructions of sections and of the whole bone. By comparison of radiodensity with the actual weight/volume of excised samples, sections are also reconstructed in terms of absolute density distribution. It is found that the spongy cetacean humerus, from its origin, is without central resorption and that its definitive structure is produced primarily by differential concentration of bone along endoectad gradients of porosity. Thus, the greatest concentration of bone is on medial and lateral sides while bone only half as dense fills the anterior and posterior sides and underlies the most dense regions. The core region is extremely porous. Within the biological context, this is a most reasonable approximation of the engineered box-beam as employed in some aircraft wings. Whole bone and frontal section radiographs show that, within this overall density pattern, the distribution of bone trabeculae resembles the classic illustrations of trajectories in the loaded beam. The ontogenetic and phylogenetic factors with possible bearing on this type of bone development and structure are discussed.

Sorex cinereus, the masked shrew, is nearly the smallest of mammals. The femur, metatarsal, phalanges and mandible of wild-trapped animals were examined by a variation in the technique of contact microradiography. Purpose of the investigation is the exploration of some aspects of the question of size as a factor in structural complexity in bone, as well as the possibilities of the shrew in studies of skeletal aging. Comparison is made with bones of the laboratory mouse and rat. Limb bones of the masked shrew are avascular. Vascularity of the mandible appears related primarily to maintenance of dental tissues. The femur is comparatively simple, its sparce spongiosa consisting of relatively large trabeculae. Diaphyseal compacta appears to be of maximum thickness for the avascular state. Tubular foot bones are without spongiosa and bone on their articular surfaces is nearly as thick as that in the diaphysis. Metatarsals and phalanges of mice have the same gross structure but are vascular. These bones in the rat have trabeculae in functional patterns. The simplicity of structure of these minute bones, and the drastic structural modification of bones of apparently starved or stressed animals, indicates potential utility of the shrew in experimental investigations.

Sera from various mammalian species, solutions of various fractions of serum proteins, and solutions of certain other substances were tested by ultrafiltration in the presence of Ca⁴⁵ and Sr⁶⁵ for their binding of Ca, and Sr. For 6 species, human, dog, horse, cow, sheep, and rat, the ratio, Ca bound/Sr bound, was 1.29, 1.14, 1.19, 1.15, 1.17, and 1.13, respectively. The absolute degree of binding shown by these species falls into 2 groups. The human, dog, and horse sera bound the 2 ions to a lesser extent, 57% Ca and 47% Sr; cow, sheep, and rat sera bound the ions to a greater extent, 69% Ca and 60% Sr. Ultrafiltration of various serum protein fractions of the human and bovine revealed that fraction V (albumin) showed no difference between the binding of Ca and Sr but differences were noted with the globulin fractions (IV, III, II) that could account for the discrimination observed in whole serum. Results of the ultrafiltration of a variety of other proteins and polyelectrolytes led to the speculation that mucoproteins in the serum globulins could account for the large fiuctuations in binding of both ions by globulin fractions of various species; however, the results did notmore » show any indication of the type of substance or chemical grouping which could account for the slight but persistent discrimination between Ca and Sr that has been observed in whole serum. (auth)« less

Until recent years, the forms of porphyria were classified on clinical grounds alone. The photocutaneous symptoms common to Gunther's congenital and chronic forms 1 have often led to confusion. Studies in this laboratory have revealed that the true porphyria congenita of Gunther is an erythropoietic disease in which the site of abnormal porphyrin formation is the developing normoblast. 2-4 In contradistinction, the chronic, or "cutanea tarda," variety belongs in the category of hepatic porphyria, the fundamental disturbance being that of a great overproduction of porphyrin by the liver. 2,3 Human erythropoietic porphyria is a rare disease; in our own roster only 7 cases are represented in a total of 255, the remainder belonging to one of the hepatic categories, either intermittent acute, cutanea tarda, or combined types. Schmid and coworkers 4 found only 34 bona fide cases in the world's literature up to 1955 but pointed out that many cases of "cutanea tarda" type

Twenty-two adult male burros were exposed to cobalt-60 radiation to the head only. Six out of seven receiving 600 r died. In contrast, six out of six burros receiving 200 r survived. Acute hematological changes observed in the 600 r irradiated group were in close agreement with early acute blood changes observed in whole-body irradiation of burros and other mammalian species. Early hematological responses were valuable prognostic aids for determining degree of brain and/or pituitary injury.

Odontocete radii are short, flattened, longer than the humeri, and lacking in open medullary cavities. Their cross-section is essentially a semi-streamlined wedge. End-on articulation at the elbow is a synchondrosis. In the streamlined, amuscular antebrachium, the radius sustains loadings predominantly in the mediallateral transverse plane as flipper movements (at the shoulder) counter body inertia and water resistance in controlling body attitude. This study treats secondary marine adaptation as reflected in radial development, growth and mechanical organization. Early osteogenesis is similar to that we reported for cetacean humeri, and parallels conditions in the manatee. Later differential growth is analyzed in extenso. Geometry of growth is visualized radiographically in the relationship of endochondral to periosteal bone in the absence of medullary cavitation. Furthermore, the neonatal outline is distinguishable within the porous structure of (only) beluga radii, so that pre- and postnatal phases may be differentiated. Radiographs and models demonstrate that as elongation occurs, circumferential increments to growth cartilages are eccentric, i.e., minimal anteriorly, moderate medially and laterally and maximal posteriorly. By this method, the centers of epiphyseal cartilage plates migrate posteriad with time. Periosteal depositions follow the same pattern and are deepest posteriorly. Eccentric growth of the ulna is in the opposite sense. Additionally, proximal growth cartilages of radii tilt posteriad as the bone elongates. Some alterations in growth occur at birth and later. Eccentric growth is an adaptation by which anterior and posterior margins, respectively, of radius and ulna move apart as the bones elongate, and by which functional cross-sections are maintained in antebrachial bones, singly and as a pair. Bone is concentrated on medial and lateral sides of the radius. This feature, and porosity of the central region, varies with species. Radii, like humeri, thus mimic an engineered box-beam, and trabecular orientation resembles trajectorial distribution in a loaded beam. Radii have higher absolute densities than do humeri, although both bones have the same range of mineralization as typical mammalian bones. The beluga radius is half again as dense as that of the pilot whale, and thus is intermediate in density between those of most odontocetes and that of the hypothyroid, pachyostotic manatee. The possible evolution of odontocete bones from a more dense dense form, as well as the phylogenetic implications of density changes, are discussed. It is suggested that some of the characteristics of growth and structure, including an apparent periodicity in structural density, may be related to temperature and vascular supply in the high-area, low-volume flipper in colder waters.