On the non-linear dynamic response of the rhesus to impact

A non-linear discrete parameter mathematical model describing the dynamic behavior of a primate (Macaca mulatta) has been developed and programmed for solution on the IBM model 360/91 computer using the Continuous Systems Modeling Program (CSMP). The primate is described by a system of discrete anatomical segments connected by translational and rotational springs representing the inter-segment stiffnesses. For example, the neck is represented by three discrete masses, one translational and four rotational springs. The masses, mass moments of inertia, centers of gravity and the neck axial stiffness, were obtained experimentally. The predicted dynamic behavior of the rhesus monkey to blunt head inpact compares favorably with the observations taken from high-speed films of a cerebral concussion experiment. A study of the effect of the point of application and angle of inclination of the forcing function was conducted. The results show that the important response parameters display the expected sensitivity to the location of the blow but are particularly sensitive to its angle of inclination with respect to the plane containing the foramen magnum.     

Comparative Immunogenicities of Chikungunya Vaccines Propagated in Monkey Kidney Monolayers and Chick Embryo Suspension Cultures

A comparative study was made of Formalin-inactivated Chikungunya vaccines prepared from the virus propagated in African green monkey kidney monolayers and concentrated chick embryo suspension cultures. The vaccine prepared in the chick embryo suspension cultures was significantly more protective to mice against a live homologous virus challenge and stimulated the production of 4 to 5 times more circulating antibodies than the vaccine prepared with virus grown in African green monkey kidney monolayer cultures.     

Primate hemoglobins: Some sequences and some proposals concerning the character of evolution and mutation

During a multipurpose survey we examined electrophoretic mobilities of major (A, i.e., ₂₂) and minor (A₂, i.e., ₂₂) adult hemoglobins from populations of nine primate genera representing a total of 440 New World monkeys and apes. Sequences of hemoglobin chains were inferred from differences in amino acid composition between homologous tryptic peptides supplemented by detailed placement of more than 270 residues. Beta sequences were thus analyzed in five genera (Aotus, Ateles, Hylobates, Saimiri, and Saguinus) and sequences in seven (foregoing plus Gorilla and Pan). In most genera, sequences from several individuals, often from several species, were delineated. Fifteen kinds of intraspecies mutants were detected; 10 of these were precisely characterized. Five of the 15 mutants form electrophoretically detected genetic polymorphisms of ; none such occur in . Six electrophoretically detected mutants, four in and two in , are uncommon. One of these represents the complete absence of minor component. Three kinds of variants, two in and one in , are electrophoretically neutral and chance findings during sequence analysis of the equivalent of 38 allele products. Two of the neutral variants are not especially common; one may have polymorphic frequency. Several general conclusions stem from these and supplementary findings. First, comparisons of sequences suggest that and genes in all primates either arose from a single event in a common ancestor or from two approximately coincident events. Either assumption allows reconstruction of a reasonably accurate archetype sequence that is effectively common to all descendants. Second, there is a pancellular quantitative disproportion between major and minor hemoglobins ranging from 16:1 to 220:1 in species studied. Delta is consequently presumed to be functionally and adaptively less vital than . When these premises are adopted, is expected to be relatively invisible to natural selection, and, where darwinism is the principal arbiter of evolution and polymorphism, is expected to show fewer fixed changes and fewer genetic polymorphisms than . The opposite is observed. Delta exhibits as many or more changes from archetype than . This finding and the comparative abundance of polymorphism are attributed to nonadaptive factors which are thus considered the source of much evolutionary change. Third, particular sequence positions in various species are the site of recurrent mutations in both and . One such area is occupied by the majority of genetic polymorphisms found in man and other primates. The overall distribution of mutations arising in evolution is remarkably nonrandom in , , and a pool of both. These results are quite unlike most other observations in higher organisms. The sources of such nonrandomness are either selection and/or differential mutability. We rely on our prior assumption of relative selective invisibility for and, in part, ascribe the nonrandom distribution of changes to microzones of enhanced mutability. Fourth, the six uncommon electrophoretically detected mutants provide an estimate of heterozygosity (1/73) at hemoglobin loci that is tenfold greater than observed in man. Fifth, the unprecedented chance detection of three kinds of electrophoretically neutral intraspecies mutants among the equivalent of 38 characterized allele products suggests that neutral changes are as common as electrostatically active ones and at least tenfold more common than expected in extrapolation from human variant surveys. Sixth, analyses from three kinds of gibbon (Hylobates) hemoglobin suggest that one of these is a potentially unchanged relict of the ancient archetype and, further, indicate a degree of homozygous diversity within a species that nearly equals the difference between gibbon and man.This investigation received support from grants to S.H.B., HD-02508-04 and K3-GM-6308-03, from the National Institutes of Health.     

Serum-mediated Immune Cellular Responses to Brucella melitensis I. Role of a Macrophate-stimulating Factor in Promoting Ingestion of Brucella by Streptomycin-protected Cells

Injection of rabbits with living Brucella melitensis Rev I induced the appearance of a macrophage-stimulating-factor (MSF) in the sera of these animals. MSF was involved in ingestion of bacilli, hastening the formation of protected loci as measured by the addition of lethal amounts of dihydrostreptomycin. When sufficient time had been allowed for effective ingestion, streptomycin had little effect. This in turn allowed for multiplication of bacilli intracellularly in the presence of 5 to 250 mug of drug per ml. MSF mediated more effective ingestion by both immune and normal macrophages. Under such conditions, there was little, if any, intracellular growth restriction by macrophages from immune animals. The activity appeared within the first 5 days after injection with 10(9) organisms and was present for several months. Three weeks after injection, the activity of serum was partially heat-labile. All activity was removed by absorption with heat-killed or living Rev I cells, suggesting that a specific globulin is concerned.     

The feeding mechanism of sharks of the family Carcharhinidae

The morphology of thefeedingapparatus in several genera of carcharhinid sharks ( Carcharhinus, Rhizoprionodon, Hypoprion, Prionace, Galeocerdo and Negaprion ) was studied in both fresh and preserved states. The actions of the cranial musculature were determined through electrical stimulation. The feeding behaviours of representatives of the genera Carcharhinus, Negaprion and Galeocerdo were studied under controlled conditions by direct observation as well as photographically. The cranial anatomy of carcharhinid sharks is characterized by a relatively reduced chondrocranium and a greatly hypertrophied musculature. The hyostylic jaw suspension serves to allow substantial cranial kinesis, particularly with respect to the upper jaw. Protraction of this skeletal element is accomplished in at least two ways, depending on the external and internal forces applied to the palatoquadrate cartilage. Under one set of conditions upper jaw protraction serves to allow precision when feeding on benthic organisms. Under quite different conditions upper jaw protraction allows the jaw to cut deeply through food items too large to be swallowed whole. The feeding mechanism found in these sharks, therefore, seems to be well adapted to deal with a wide variety of food types.     

Bacterial Vaccine in Multidose Tablet Form for Parenteral Use

Dried typhoid vaccines were prepared by freeze-drying of heat-inactivated phenolized-cell suspensions and by an acetone-killed and dried technique. Portions of the dried powder obtained by each method were compressed into tablets. Tests with the products showed that drying and making of tablets did not affect the ability of the vaccines to protect mice or elicit antibodies in rabbits.     

THE EXCRETION OF DIGITOXIN

By noting the reaction of embryonic duck hearts to solutions containing digitoxin, it is possible to detect as little as 2 micrograms of digitoxin in 24-hour urine samples of rats and of human subjects.Rats were given large doses of digitoxin intraperitoneally and their 24-hour urine production collected. A minimal quantity of digitoxin was detected in the urine. A minimal quantity of digitoxin was detected in the first three 24-hour urine samples of human subjects given 1.2 mg. of digitoxin. These results show that by this method the measurable urinary excretion of digitoxin in the rat and in human subjects is small.     

An Electron Microscopic Study of the Intestinal Villus : I. The Fasting Animal

The structure of the intestinal villus of the rat was studied in thin sections of tissue fixed in buffered osmium tetroxide and embedded in methacrylate. The simple columnar epithelium investing the villus is surmounted by a striated border consisting of slender projections of the cell surface. These microvilli are arranged in almost crystalline, hexagonal array, and increase the apical surface area of the cell by a factor of 24. The core of each microvillus is filled with fine fibrils which arise from the filamentous substance of the terminal web underlying the striated border. Each microvillus is covered by a tubular extension of the plasma membrane of the epithelial cell. Pinocytotic vesicles originating from the plasma membrane occur at the bases of the intermicrovillous spaces. The nucleus, mitochondria, and the endoplasmic reticulum of the epithelial cell display no unusual features. Small bits of ergastoplasm occur in the apical cytoplasm. A thin basement membrane separates the epithelium from the lamina propria which consists of vessels, nerves, and numerous lymphocytes, eosinophiles, mast cells, plasma cells, smooth muscle fibers, and macrophages suspended in a delicate stroma of fibroblasts and collagen fibers. Intercellular fat droplets often occur in this stroma, even in animals fasted for 40 hours. The blood capillaries are distinguished by their extremely attenuated, fenestrated endothelial cells. The lacteal has a thicker endothelium which, although not fenestrated, appears to have significant interruptions, especially at the margins between neighboring lining cells. Strands of smooth muscle always accompany the lacteal but do not form an integral part of its wall. Unmyelinated nerves, many of which are too small to be distinguished with the light microscope, course through the lamina propria in association with the vessels. The nerve fibers evidently do not cross the basement membrane into the epithelium. Neuromuscular junctions or other terminal apparatus were not found.