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  • 1965-1969  (20)
  • Life and Medical Sciences  (10)
  • Polymer and Materials Science  (9)
  • Analytical Chemistry and Spectroscopy  (1)
  • Biochemistry and Biotechnology
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  • 1
    Electronic Resource
    Electronic Resource
    Heat of the reaction forming the three-stranded poly (A + 2U) complex (1965)
    New York : Wiley-Blackwell
    Biopolymers 3 (1965), S. 491-496 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Calorimetric measurements of the heat of the addition of the second strand of poly U to poly (A + 2U) to form the three-stranded poly (A + 2U) complex in 0.1M and 0.5M NaCl at 24 and 37°C. are reported. A value of ΔH = -3800 cal./mole of poly (A + 2U) formed was found to be fairly insensitive to the experimental conditions employed. The heat of the addition of the third strand to the preformed poly (A + U) helix is considerably less exothermic than the heat of reaction between poly A and poly U to form poly (A + U). The insensitivity of the heat of addition of the third strand (poly U) to changes in salt concentration and temperature lends qualitative support to the earlier hypothesis that the major portion of the variation of the ΔH of the poly A and poly U reaction with experimental conditions arises from differences in the conformation of poly A. Combining the information obtained in this study for the ΔH of the reaction forming poly (A + 2U) with data for the ΔH of the formation of poly (A + U) indicates that the conversion of poly (A + U) to poly (A + 2U) is opposed by an enthalpy change which increases with temperature. Extrapolation of these values to 52°C. where poly (A + U) is transformed to poly (A + 2U) in 0.5M NaCl leads to a value of ΔH = +3800 cal./mole (A + 2U) formed and ΔS = 11.5 cal./mole of (A + 2U) formed. It is concluded from the calorimetric data that the driving force for the poly (A + U) to poly (A + 2U) conversion reaction is the favorable entropy change.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1965.360030410
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  • 2
    Electronic Resource
    Electronic Resource
    Viscosity study of DNA. II. The effect of simple salt concentration on the viscosity of high molecular weight DNA and application of viscometry to the study of DNA isolated from T4 and T5 bacteriophage mutants (1968)
    New York : Wiley-Blackwell
    Biopolymers 6 (1968), S. 1005-1018 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Polyelectrolyte expansion effects on high molecular weight bacteriophage DNA have been studied by examining the influence of simple salt concentration upon the intrinsic viscosity, [η]. The viscosity-molecular weight exponent a in the expression [η] = KMa diminishes from 0.8 in 0.005M simple salt to a limiting value of 0.6 for salt concentrations greater than 0.6M at 25°C. The ε parameter of the N1+ε hydrodynamic representation thus varies from approximately 0.2-0.07 over this range of salt concentration. The intrinsic, viscosity of DNA decreases slightly with increasing temperature at low and moderate salt concentrations but becomes independent of temperature at high salt concentrations. The expansion of the DNA molecular domain is linear in the reciprocal square root of the simple salt concentration. Viscosity differences among DNA's isolated from several bacteriophage T5 mutants reflect small differences in molecular weight which are in agreement, with sine determination by other techniques. The DNA's isolated from various rII mutants of T4 bacteriophage including some very large deletion mutations were found to be identically the same size in accord with current genetic ideas. Details of the representation and extrapolation of viscosity data are discussed and the sensitivity of the technique is evaluated.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1968.360060802
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  • 3
    Electronic Resource
    Electronic Resource
    Ionic polysaccharides. II. Comparison of polyelectrolyte behavior of hyaluronatc with that of carboxymethyl cellulose (1968)
    New York : Wiley-Blackwell
    Biopolymers 6 (1968), S. 1519-1529 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Sodium hyaluronate (NaHy) and sodium carboxymethyl cellulose (NaCMC) behave similarly with respect to concentration.N 3 of an added 1 : 1 electrolyte. The second virial coefficient A2 (light scattering) is identical within experimental error at a given.N 3. The limiting viscosity number [η] also varies with N3-1/2in similar fashion for samples of similar [η] of the two polymers. Differences in Na+ activity in salt-free solutions are interpreted on the basis of weaker Na+ binding in NaHy, presumably due to the greater charge separation along its chain backbone. Added electrolyte is excluded in dialysis more strongly by NaHy (or its acid form) than by NaCMC. The Flory parameter Φ is smaller in good solvents for NaHy, as for many other polyelectrolytes, than for nonionic polymers.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1968.360061102
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  • 4
    Electronic Resource
    Electronic Resource
    The fine structure of campaniform sensilla on the halteres of Drosophila melanogaster (1969)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 128 (1969), S. 443-463 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The campaniform sensilla on halteres of Drosophila were studied by electron microscopy in order to establish the relationships of functional elements in the sensory system. The surface of the sensillum consists of an oval cuticular cap membrane which may contain resilin, the rubberlike protein. A border of denser cuticle rings the cap membrane, and extending down around the neural process is a third type of cuticle filled with a fourth light fibrous type. The four cuticular components form a system for displacement of the neural process. The neural process is differentiated into a terminal fan-shaped structure projecting from a bulbous dilatation which tapers to a neck region ending proximally with two basal bodies. The neural process is packed with microtubules. Surrounding the dendrite is an inner enveloping cell, attached to the basal body region by septate desmosomes and by desmosomes to which microtubules of the enveloping cell are applied. An outer enveloping cell surrounds the inner one. The tip of the neural process is covered with a dense secretion which is tightly bound to the cap membrane. The dense secretion is surrounded by an extracellular fluid which might be compressed hydraulically by the cuticular system. The stimulus of cuticular distortion could thus be transmitted to the neural process which may be displaced between its fixed ends.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051280405
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  • 5
    Electronic Resource
    Electronic Resource
    Theory of a rapid method for determining molecular weights of giant molecules (1969)
    New York : Wiley-Blackwell
    Biopolymers 7 (1969), S. 87-97 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new method is proposed for finding molecular weights from the boundary condition of the ultracentrifuge. The method is more rapid than the conventional Archibald method by at least one order of magnitude and should be especially useful for giant molecules with small diffusion coefficients. It employs a preset concentration gradient. A theoretical study of the method has been made by obtaining solutions to the Lamm equation analogous to the “mirror image” solution (for early times) and the Fourier expansion solution (for late times) of Mason and Weaver. Numerical examples of theoretical results are given, and the errors are discussed. Centrifugation in a preset linear gradient can also be used to reduce the time needed to reach equilibrium.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1969.360070109
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  • 6
    Electronic Resource
    Electronic Resource
    Denaturation of RNA with dimethyl sulfoxide (1968)
    New York : Wiley-Blackwell
    Biopolymers 6 (1968), S. 793-807 
    Details
    ISSN: 0006-3525
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The denaturation of single-stranded and double-stranded RNA's in solutions with varying proportions of dimethyl sulfoxide has been followed by changes in absorbancy, optical rotation, and - with a double-stranded form of bacteriophage of MS2 RNA -  infectivity for bacterial spheroplasts. By these criteria the RNA's studied, including the synthetic polynucleotide rG:rC, are completely denatured at room temperature in high concentrations of this solvent. In lower concentrations, the Tm of the RNA preparation is decreased only slightly as the dimethyl sulfoxide concentration is raised until a critical concentration is reached. The Tm falls sharply with small further increases in dimethyl sulfoxide concentration. Sedimentation studies can be conducted directly in these media. The determination of sedimentation velocity in 99% dimethyl sulfoxide containing 0.001M EDTA provides a reliable estimate of RNA molecular weights.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bip.1968.360060604
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  • 7
    Electronic Resource
    Electronic Resource
    Cellular dynamics in the jejunum of essential fatty acid deficient miceThis work was supported by USPHS grant 5-T01-CA-05007-10.This investigation represents a portion of a thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Division of Biological and Medical Sciences, Brown University. (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 159 (1967), S. 421-429 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The population dynamics of the jejunal epithelium of mice maintained on a semi-synthetic diet deficient in the essential fatty acids (EFA) has been investigated. Colchicine was employed to collect mitotic figures for the determination of mitotic indices. Twenty-five crypts in longitudinal section were counted per animal and the mean mitotic index computed as the number of mitoses per total number of crypt cells. EFA-deficient animals had a mean mitotic index of 36.56 as compared with 26.51 and 16.74 for the linoleic acid-supplemented and chow-fed control animals, respectively. Counts of the number of epithelial cells on one side of a villus and crypt indicated that the height of the villi, but not the crypts, of the EFA-deficient animals was significantly lower than either control group. In the EFA-deficient animals the mean percentage of villi having extrusion zones exceeded that of both control groups. Radioautography demonstrated that 36 hours after injection of tritiated thymidine the majority of villi in the EFA-deficient animals were labeled at their tips, whereas in control samples label was restricted to the lower one-half to three-fourths of the villus. Thus, EFA-deficiency induces increased rates of mitosis, migration and sloughing, resulting in alterations in villous architecture.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091590411
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  • 8
    Electronic Resource
    Electronic Resource
    Collection of mouse semen by electroejaculationSupported in part by grant HD-00543 from the National Institutes of Health, Public Health Service. Technical assistance by Robert M. Callahan. (1966)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 155 (1966), S. 11-14 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Liquid and coagulated ejaculates were collected separately from mice by electroejaculation. Sperm concentrations in the liquid ejaculates from 51 animals ranged between 25,000 and 2,228,000/mm3 and total number of spermatozoa per ejaculate between 60,000 and 5,464,000. This method is suggested as a practical means of obtaining ejaculated spermatozoa free of coagulum for reproduction research.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091550103
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  • 9
    Electronic Resource
    Electronic Resource
    The effects of ovarian hormones on uterine phosphatases of the rhesus monkey (Macaca Mulatta) (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 157 (1967), S. 465-479 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Endometrial acid and alkaline phosphatases were studied histochemically in rhesus monkeys treated with various combinations of estrogen (E, 17β-estradiol and/or estriol), progesterone (P) and relaxin (R) or a low potent relaxin control preparation (NRF). In the cells of the uterine glands of the E-treated animal, the apical cytoplasm showed intense activity of both phosphatases. This estrogenic response was depressed in the stratum functionale by P and in the stratum basale by PR. With E, acid phosphatase-staining granules appeared in scattered stromal cells with eccentric nuclei. Addition of P or PR increased the number of acid phosphatase positive stromal cells, especially in the stratum functionale. With the exception of the sinus-like channels and superficial vessels of the stratum functionale of monkeys treated with ER and EPR, all endothelium of capillary and precapillary vessels was rich in alkaline phosphatase activity. Thus, acid alkaline phosphatases appear to be metabolically important components of the endometrium which undergo cyclic variation and reflect specific influences of the ovarian hormones; estrogens, progesterone and relaxin. The implications to human menstrual physiology are discussed.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091570307
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  • 10
    Electronic Resource
    Electronic Resource
    An analysis of the growth retarding effects of trypan blue in the albino ratsSupported by NIH Research grant HD630, T-141. (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 159 (1967), S. 453-458 
    Details
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A laparotomy was performed on 74 pregnant Wistar rats after eight days of gestation and injection with trypan blue, normal rabbit serum, or sterile saline. Also, a laparotomy was performed on a control group which received no injections. After 21 days of pregnancy, the rats were sacrificed and the fetuses and their placentae removed, weighed individually, and then fixed in Bouin's fixative. All fetuses were dissected and examined for abnormalities. Several analyses of variances and a paired t-test were completed to determine if fetal growth was retarded in the abnormal fetuses. Fetuses in each experimental group were also separated into weight classes as determined by Sturge's Law for class intervals. It was shown that in inbred colonies the timing of the pregnancy, litter size, and maternal factors cannot be neglected. The results indicate that: (1) Trypan blue exerts a definite growth retarding effect on rat fetuses; (2) The weights of malformed fetuses are significantly reduced; (3) The mean term fetal weight of the normal fetuses that were exposed to trypan blue is not significantly different from the mean weight of the control normal fetuses; (4) The mean weight of the abnormal fetuses that were exposed to trypan blue is significantly less than that of the control normal fetuses as well as the normal fetuses treated with trypan blue; (5) There is no weight threshold below which all fetuses are abnormal and above which all fetuses are normal.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ar.1091590414
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