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  • 1990-1994  (6)
  • 1960-1964  (1)
  • Life and Medical Sciences  (3)
  • Biochemistry and Biotechnology  (2)
  • Molecular mechanics  (2)
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Years
Year
Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of computer aided molecular design 5 (1991), S. 21-39 
    ISSN: 1573-4951
    Keywords: Partial charge ; Charge calculation ; Molecular mechanics ; Force field comparison
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The CHARGE2 programme, which involves the classical calculation of both the inductive and resonance contributions to the partial atomic charges in molecules is described, and the charges and electrostatic potentials obtained presented for some illustrative examples. In substituted methanes (CH3X, CF3X, CCl3X) the effects of varying the electronegativity of the substituents and the α- and β-substituent contributions are clearly illustrated for a variety of substituent groups X. The problems involved in the inclusion of silicon into this scheme are detailed, together with the methods of overcoming them. The partial atomic charges (σ and π contributions) and electrostatic potentials for some silicon oxygen compounds are presented and discussed. The partial atomic charges from CHARGE2 for all the natural amino acids as their N-acetyl, N′-methyl-amides are given and compared with those obtained from the AMBER and ECEPP/2 force fields. Considerable differences in these figures are observed, with the AMBER charges consistently much larger than those from the other two methods. The CHARGE2 partial atomic charges and electrostatic potentials for the four common nucleic acids, adenine, cytosine, guanine and thymine, are given and compared with those derived from other calculations. Again there is general similarity but also there are considerable differences, with those from the AMBER force field somewhat larger than the other methods.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of computer aided molecular design 5 (1991), S. 205-212 
    ISSN: 1573-4951
    Keywords: Conformational energies ; Piperidines ; Piperidinium salts ; Molecular mechanics ; Solvation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The conformational free energies (-ΔGo) of a number of 4-substituted piperidines and piperidinium salts have been determined by the J-value method. For the 4-substituted piperidines (R=Me, Phenyl, CO2Et, Br, OH, F) the relative conformer energies are almost identical to those of the analogous cyclohexanes. The methyl and phenyl compounds showed no change in the couplings on protonation, implying no change in the conformer energies. In constrast, in the remaining compounds with polar 4-substituents an almost constant stabilisation of the axial conformer of ca. 0.7–0.8 kcal mol-1 was observed on protonation. In three cases (R=F, OH and Br) the conformational preferences is reversed on protonation and the axial form is favoured. The conformer energies of both the free bases and the piperidinium salts can be quantitatively predicted by molecular mechanics calculations using the COSMIC force-field, in which the electrostatic interactions are calculated by a simple Coulombic model with the partial atomic charges in the molecules given by the CHARGE2 routine, and an effective dielectric constant of five. The precise agreement obtained demonstrates conclusively that the electrostatic interactions between the substituents and the protonated nitrogen are the cause of the conformational changes on protonation, and that these can be modelled successfully using existing force-fields.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Proteins: Structure, Function, and Genetics 7 (1990), S. 366-377 
    ISSN: 0887-3585
    Keywords: computer modeling ; protein ; structure ; α-carbons ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A procedure for the construction of complete protein structures from only αcarbon coordinates is described. This involves building the backbone by sequential addition of Pro, Gly, or Ala residues. This main chain structure is then refined using molecular dynamics. Side chains are constructed by sequential addition of atoms with intermediate molecular dynamics refinement. For α lytic protease (a structure that is mostly β sheet) a backbone root mean square deviation (RMSD) of 0.19 Å and an overall RMSD of 1.24 Å from the crystallographic coordinates are attained. For troponin C (67% β-helix), where the coordinates are available only for the α-carbons, a backbone RMSD of 0.41 Å and an overall RMSD of 1.68 Å are attained (fits kindly provided by Dr. Michael James and Natalie Strynadka). For flavodoxin a backbone RMSD of 0.49 Å and an overall RMSD of 1.64 Å were attained.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 44 (1994), S. 1315-1324 
    ISSN: 0006-3592
    Keywords: static mixer ; MRC-5 ; anchorage dependent ; hepatitis A ; animal cell culture ; bioreactor ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The titanium static mixer reactor, demonstrated for a variety of vaccine processes during the late 197s, was investigated for the production of attenuated hepatitis A virus antigen from anchorage-dependent MRC-5 cells. This reactor system used Charles River Biotechnological Services cabinets for monitoring and process control. Cell inoculation protocols, using 6000-10,000 cells/cm2, resulted on over 95% attachment at both the laboratory and pilot scales. Indirect monitoring techniques using oxygen, glucose, L-serine, and L-glutamine uptake rates were indicative of cell growth prior to virus inoculation as well as environmental and/or nutrient limitations. Seven laboratory-scale (3900 cm2) runs and one pilotscale (265,000 cm2) run were conducted to investigate refeeding regiments, parallel versus perpendicular element orientation, increased element surface area per unit volume, and scale-up performance. In general, lysate antigen yields achieved were similar to those of parallel T-flasks cultivated under similar conditions. © 1994 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 142 (1962), S. 531-535 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 50 (1992), S. 120-127 
    ISSN: 0730-2312
    Keywords: intravesical therapy ; superficial bladder cancer ; transitional cell carcinoma ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Approximately 70% of all bladder cancers are superficial at the time of presentation. Superfecial bladder cancer includes tumors confined to the urothelium (clinical stage Ta) or lamina propria (stage T1) and flat carcinoma is situ (stage Tis). Because the biological behavior of bladder neoplasms is variable, several important prognostic factros must be addressed. Multivariate analyses have shown that factors predictive of tumor recurrence and tumor progression include multifocal tumors, high grade tumors. T1 tumors and positive urinary cytology after transurethral resection (TUR). The patient with superficial bladder cancer should be monitored via endoscopy supplemented by urinary cytology, using either voided or bladder irrigation specimens and urinalysis. Frequent intravenous urography is not required, even in high grade tumors, as long as the clinical and pathologic studies remain negative and the patient is asymptomatic.The “gold standard” of treatment for superficial is TUR of the entire tumor. Despite TUR, new tumors will occur in approximately 50% of all patients; those at highest risk for tumor recurrence and progression require adjuvant intravesical therapy after TUR. A variety of drugs are used as intravesical therapy, including thiotepa, mitomycin C, doxorubicin hydrochloride, Bacillus Calmette-Guerin (BCG), epirubicin, and interferon. Although associated with the most toxicity, BCG appears to be the most effecacious agent in increasing the time to recurrence and progression and in reducing the recurrence rate. © 1992 Wiley-Liss, Inc.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 144 (1990), S. 77-83 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The expression of the early genes JE and KC has been examined in Balb/c 3T3 cells treated with bacterial lipopolysaccharide (LPS). Previous studies showed that JE and KC mRNAs are induced in murine peritoneal macrophages treated with LPS, suggesting a role for these genes in inflammatory responses. Consistent with this possibility are recently published cDNA sequences which document that both genes are members of a superfamily of inflammation- and/or growth-related cytokines. In the present study, we provide evidence that the mRNAs for JE and KC are specifically induced by LPS treatment of Balb/c 3T3 cells. The LPS-stimulated expression of JE and KC was dose dependent, and exhibited a transient time course; message levels were maximal between 2 and 4 hr and declined by 8 hr. The LPS-augmented accumulation of JE and KC occurred even in the presence of cyclohexamide, which additionally had a superinducing effect on the expression of both genes. Cyclohexamide alone, in the absence of LPS, also induced JE and KC mRNA accumulation. LPS-stimulated JE and KC mRNA expression was dependent upon the stimulation of transcription as determined by nuclear “run-on” studies. Comparative analyses indicated that, under the conditions employed, LPS was a somewhat less effective stimulant of JE expression than PDGF or EGF, and was more effective than PDGF and equivalent to EGF in its ability to augment KC accumulation. Unlike PDGF and EGF, LPS did not stimulate DNA synthesis by Balb/c 3T3 cells at any time over the 72 hr period examined. The ability of the inflammatory, non-mitogenic stimulus LPS to selectively induce JE and KC mRNA expression by fibroblasts may reflect their participation in inflammation and wound healing as secretory cells.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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