Effects of dynamic impacts on human bones

Flat bones of human skeleton were subjected to dynamic indentation with ball indenters. The impacted surface was studied under high magnification and also by using the technique of multiple beam interferometry. The impulse caused the pile up of material at a little distance from the edge of the indent. The diameter of indent is found to increase as fourth root of the energy of impact. Bone structure also has the tendency to minimize the damage caused by external forces. There was about 90% recovery in deformation in the depth of indents due to internal stresses created inside the bone by the impact.     

The maximum leaf surface temperatures of the higher plants observed in the Inland Sea area

The maximum leaf surface temperatures (MLSTs) of 126 species of higher plants were measured by means of an infrared thermometer, in the Inland Sea area, southwest of Honshu-Island, Japan, where plants suffered from severe environmental conditions due to an abnormally small amount of precipitation during the summer of 1978. The MLSTs of plants in the summer of 1978 were greater than or equal to those of 1979, when the environmental conditions were not so severe. The MLST measured in this study was 50.4 C for a non-succulent plant (Liriodendron), and 53.1 C for a succulent plant (Agave). Plants with different life forms appeared to have different MLSTs. The average of the MLSTs of conifers deciduous trees, and evergreens were 36.4, 37.7, and 40.3 C, respectively. This order corresponds to the distribution of forests from high to low, latitudes. Also the MLSTs were higher for woody plants than for herbaceous plants. Relatively high leaf temperatures were observed for climbing plants, both herbaceous and woody. Plants with narrow leaves had lower leaf surface temperatures than those with borad leaves. Herbaceous dicotyledonous plants actively growing at the end of the summer of 1978, in full sun at Hiroshima Castle were exclusively those with relatively high leaf temperatures.     

Plate-Induced tumors of BALB/3T3 cells exhibiting foci of differentiation into pericytes,chondrocytes, and fibroblasts

The BALB/3T3 clone A31 mouse embryo cell line has been used by many investigators as a model “normal” “fibroblast” line for a variety of in vitro studies. It has been shown, however, that these cells are not “normal” because they will produce tumors within 2–4 months if 3 × 10⁴ cells are implanted subcutaneously in BALB/c mice attached to 0.2 × 5 × 10-mm plastic plates. Previous studies also suggested that these cells were not fibroblasts because they gave rise to tumors with the characteristics of vascular endothelium not fibroblasts. We now report that BALB/3T3 (clone A31), BALB/3T3-T, a proadipocyte subclone of clone A31 cells, and six recent subclones of BALB/3T3-T cells show additional differentiation patterns when tumors derived by implantation of these cells attached to plastic plates are examined. Differentiation into pericytes, chondrocytes, and fibroblasts was observed. We conclude that the BALB/3T3 clone A31 cell line and related lines are multipotent mesenchymal cells which are capable of differentiation into a variety of cell types.     

Isolation of a high molecular weight glycoconjugate derived from the surface of S purpuratus eggs that is implicated in sperm adhesion

Sea urchin sperm–egg adhesion is mediated by bindin, a sperm surface protein that has lectin-like activity. Bindin agglutinates eggs, and this interaction has been shown to be inhibited by glycopeptides released from the egg surface by protease treatment. In this study, we report the purification and properties of such an egg surface glycoconjugate that may be involved in sperm adhesion. The glycoconjugate was partially purified by gel filtration and affinity chromatography on bindin particles. Upon gel filtration on Sepharose CL 4-B, the glycoconjugate elutes near the void volume, suggesting that it has a molecular weight in excess of one million. In addition, we have found that the egg surface glycoconjugate agglutinates bindin particles, indicating that it is multivalent. Carbohydrate analysis indicates that the glycoconjugate is composed primarily of fucosc, xylose, galactose, and glucose. This purified egg surface component is the most potent inhibitor of bindin-mediated egg agglutination yet described.     

Sperm–egg binding: Identification of a species-specific sperm receptor from eggs of strongylocentrotus purpuratus

We have attempted to identify a surface component of echinoderm eggs that is involved in the species-specific binding of sperm. Cell surface membranes from eggs of the sea urchins Strongylocentrotus purpuratus or Arbacia punctulata were radioiodinated, detergent-treated, and subjected to density-gradient centrifugation. In the presence of bindin, the complementary binding protein isolated from sperm, one component of the membranes sedimented to a different density. This membrane component bound-species specifically to sperm that had undergone the acrosome reaction. This binding led to an inhibition of the ability of treated sperm to fertilize eggs. Exhaustive proteolytic digestion of this receptor fraction yields a high molecular weight glycopeptide that can also bind to bindin. It therefore appears that this egg surface membrane fraction contains a functionally intact, species-specific receptor for sperm.     

Lectin-mediated sperm agglutination of bufo arenarum and leptodactylus chaquensis spermatozoa

Various plant lecins were employed in cell agglutination experiments to ascertain the presence of specific saccharides in the surface of B arenarum and L chaquensis spermatozoa. B arenarum spermatozoa were specifically agglutinated with Concanavalin A (Con A), phytohemagglutinin P (PHA-P), and wheat germ agglutinin (WGA), but not with soybean agglutinin (SBA). In contrast, L chaquensis spermatozoa were strongly agglutinated by SBA, WGA, and PHA-P. L chaquensis spermatozoa did not agglutinate with Con A even at high concentrations. Lectinmediated sperm agglutination was inhibited in the presence of specific lectinbinding sugars. Spermatozoa from both species were agglutinated randomly with all lectins suggesting a uniform distribution in the sperm surface of the lectinbinding saccharide ligands. B arenarum sperm agglutination induced by Con A is sensitive to temperature. B arenarum spermatozoa are more agglutinable at 24°C than at 4°C. These results suggest that lectin-binding site mobility is necessary for sperm agglutination.     

Sex differences in the Ilia of a known sex and age sample of fetal and infant Skeletons

Ilia from a known sex, race, and age sample of fetal and infant skeletons from the collections of the Smithsonian Institution were evaluated for six metric and one nonmetric characters. Three indices calculated from the measurements were analyzed. The nonmetric trait was examined for fit with known sex. The three indices failed to show significant sex differences. The nonmetric trait, Auricular Surface Elevation, proved dependable (91% accurate) for the male Fetal and Six Month age groups.     

Plasmodium falciparum: loss of knobs on the infected erythrocyte surface after long-term cultivation.

After long-term in vitro cultivation in human erythrocytes, variants of three strains of the malaria parasite Plasmodium falciparum no longer produce the “knob” alterations on the host erythrocyte surface. The time in continuous culture before knobs failed to appear ranged from 18 months for the Gambian strain FCR-4 to 33 months for the Vietnamese strain FCR-1. The loss of knobs is correlated with the inability to concentrate trophozoites, schizonts, and segmenters from these variant lines by the use of gelatin-containing media. This is the first report of a change in Plasmodium falciparum or its host cell as a consequence of long-term culture.     

The mechanism of voltage-sensitive dye responses on sarcoplasmic reticulum

Summary The mechanism of voltage-sensitive dye responses was analyzed on sarcoplasmic reticulum vesicles to assess the changes in membrane potential related to Ca²⁺ transport. The absorbance and fluorescence responses of 3,3-diethyl-2,2-thiadicarbocyanine, 3,3-dimethyl-2,2-indodicarbocyanine and oxonol VI during ATP-dependent Ca²⁺ transport are influenced by the effect of accumulated Ca²⁺ upon the surface potential of the vesicle membrane. These observations place definite limitations on the use of these probes as indicators of ion-diffusion potential in processes which involve large fluctuations in free Ca²⁺ concentrations. Nile Blue A appeared to produce the cleanest optical signal to negative transmembrane potential, with least direct interference from Ca²⁺, encouraging the use of Nile Blue A for measurement of the membrane potential of sarcoplasmic reticulumin vivo andin vitro. 1,3-dibutylbarbituric acid (5)-1-(p-sulfophenyl)-3 methyl, 5-pyrazolone pentamethinoxonol (WW 781) gave no optical response during ATP-induced Ca²⁺ transport and responded primarily to changes in surface potential on the same side of the membrane where the dye was applied. Binding of these probes to the membrane plays a major role in the optical response to potential, and changes in surface potential influence the optical response by regulating the amount of membrane-bound dye. The observations are consistent with the electrogenic nature of ATP-dependent Ca²⁺ transport and indicate the generation of about 10 mV inside-positive membrane potential during the initial phase of Ca²⁺ translocation. The potential generated during Ca²⁺ transport is rapidly dissipated by passive ion fluxes across the membrane.