Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This paper represents an initial step in applying to complex clinical situations the symbolic logic developed by G. Spencer Brown and elaborated by Francisco Varela. This way of modeling turns out to yield an interesting mixture of rigidity, ambiguity, and paradox, perhaps inevitable at our present level of understanding of systems containing feedback. Applying the Brown-Varela concepts seems a useful transitional step toweard the future use of more sophisticated quantitative models such as those of Powers and Forrester.
Fam Process 1979 Dec
PMID:Using systems theory to organize confusion. 52 6

The chromatographic separation and biochemical characterization of a beta-bungarotoxin is described. This toxin is isolated as the most basic eluting protein of Bungarus multicinctus venom when separated by column chromatography on CM-Sephadex C-25. The protein migrated as a single band on pH 4.3 and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. The molecular weight of this toxin was estimated to be 10 000 +/- 1000 by analytical sedimentation analysis. This value was consistent with the electrophoretic mobility of the toxin in SDS-polyacrylamide gels. The amino acid composition of this 11 000-dalton beta-bungarotoxin was similar to that of the 22 000-dalton beta-bungarotoxin previously reported (Lee et al. (1972) J. Chromatogr. 72, 71--82; Kelly, R.B. and Brown, III, F.R. (1974) J. Neurobiol. 5, 135--150; Kondo et al. (1978) J. Biochem. Tokyo 83, 91--99), suggesting that the 11 000-dalton toxin may be one of the polypeptide chains of the larger toxin. The 11 000-dalton beta-bungarotoxin was toxic to mice when injected intravenously. Animals that received lethal doses exhibited hyperexcitability followed by ataxia, convulsions, and death. The minimum lethal dose was 0.12 microgram/g body weight. This beta-bungarotoxin exhibited Ca2+-dependent phospholipase A activity comparable to that of the 22 000-dalton beta-bungarotoxin. The enzyme exhibited phospholipid substrate specificity in the rank order of phosphatidyl-choline, phosphatidylserine, phosphatidylethanolamine, and phosphatidyl-inositol. The enzyme activity was destroyed by boiling for 3 min at pH 8.6. In addition, an enzymatically inactive quantity of the 11 000-dalton toxin, equivalent to five times the minimum lethal dose of enzymatically active toxin, was not lethal when injected into mice. To test whether phospholipase A activity is responsible for lethality, bee venom phospholipase A2 was injected into mice at similar and greater concentrations with no toxic effect. Thus, while phospholipase A activity may be required for the lethal effect of the 11 000-dalton beta-bungarotoxin, the specificity of action of the toxin is not determined by its enzyme activity.
Biochim Biophys Acta 1978 Dec 20
PMID:Purification and biochemical characterization of an 11 000-dalton beta-bungarotoxin. 56

The importance of IgG attached to protein A in the initial reaction of inspired Staphylococcus aureus and alveolar macrophages was studied by infecting unimmunized mice with aerosols of S. aureus strains 566 and Wood 46 with high and low protein A content. At 2, 4, and 8 hr after infection, the presence of IgG attached to S. aureus and rates of staphylococcal ingestion and killing by macrophages were determined. IgG was detected by staining of sections of the right lung with fluorescein-labeled goat antibody to mouse IgG. For S. aureus strain 566, 25%--40% of the total number of bacteria, as determined in equivalently sized subjacent sections stained by the Brown and Brenn tissue gram stain, contained attached IgG. A few S. aureus strain Wood 46 were surrounded by dimly fluorescing complexes. Since rates of bacterial ingestion and killing were similar for both strains in this in vivo model of infection, IgG binding to protein A does not affect the bactericidal capacity of alveolar macrophages.
J Infect Dis 1978 Dec
PMID:Effect of protein A on the antistaphylococcal defence mechanisms of the murine lung. 73 55

1. The tension developed by a muscle in response to a single supramaximal nerve volley is often the sum of two contractions, the second resulting from re-excitation of some nerve terminals during the first contraction. Re-excitation or back-firing can be prevented if the muscle nerve is stimulated twice with the second volley arriving in the muscle at a time when muscle fibres are still refractory following the first volley (Brown & Matthews, 1960). 2. Back-firing has been studied here in the medial gastrocnemius muscle of the spinal cat and responses have been recorded, either representing the summed activity of the muscle's motor supply or discharges of single functional motor axons. 3. When stimulating at a distance from the muscle, the second of two shocks is effective in suppressing back-firing over a narrower range of stimulus intervals than when stimulating close to the muscle. 4. The amount of back-firing can be reduced by stretching the muscle. At a length corresponding to the optimum for a twitch little if any back-firing remains. 5. Measurements of threshold to electrical stimulation of single functional motor axons suggests that low threshold axons are more likely to show back-firing. In the majority of cases, most or all of the motor units in the muscle have to be active before back-firing can be observed.
J Physiol 1978 Dec
PMID:Further observations on back-firing in the motor nerve fibres of a muscle during twitch contractions. 74 26

The preparation of dispersed parathyroid cells by collagenase digestion of porcine parathyroid glands, essentially as outlined by Brown et al. (Endocrinology 99: 1582, 1976), is described. The cells secrete parathormone linearly for at least 4 h of incubation and rapidly respond in inverse fashion to changes in the medium calcium and magnesium concentrations over the range 0.5-3.0 mM. In terms of inhibition of secretion, either ion was more effective in the presence of a minimum concentration of the other, indicating that calcium and magnesium affect separate cellular sites. Parathormone was identified both by immunoassay of the whole incubation medium and by its separation by polyacrylamide gels and carboxymethylcellulose chromatography. When the cells were incubated with radioactive amino acids and both the medium and cells were subsequently analyzed on gels, we found that parathyroid secretory protein as well as parathormone and some immunoactive fragments were present. Analysis of the radioactive protein contained in the cells at high and low calcium concentrations revealed that calcium decreased the formation of the secretory protein by approximately 40% without appreciably affecting the formation of proparathormone or parathormone. The secretion of both parathyroid secretory protein and parathormone were inversely proportional to the concentrations of medium calcium or magnesium. The secretion of the latter, however, was more sensitive (95% inhibition) than parathormone (40-60% inhibition) to changes in medium divalent cations. These results suggest that the synthesis, intracellular processing, or secretion of parathormone and parathyroid secretory protein utilize independent calcium- and magnesium-regulated pathways.
Endocrinology 1978 Dec
PMID:The effects of calcium and magnesium on the secretion of parathormone and parathyroid secretory protein by isolated porcine parathyroid cells. 74 33

A radioimmunoassay for detection of antitubular basement membrane (TBM) antibodies was set up using a human TBM antigen (mol wt, 70,000 daltons), purified after collagenase treatment of the insoluble membrane by preparative polyacrylamide electrophoresis, and labeled with iodine 125. Free labeled antigens were separated from those bound to immunoglobulins by a 20% polyethylene glycol (mol wt, 6,000 daltons) solution. In the presence of normal human or Brown Norway rat sera, less than 10% of the labeled antigens were precipitated. In the presence of sera or of kidney eluates from rats immunized with human TBM, the precipitation of the labeled TBM antigens reached 73%, but in the presence of sera from two patients presenting with an interstitial nephritis and linear deposits along the TBM only, up to 47% of the same antigens were precipitated. In these two cases, the anti-TBM antibodies were mainly directed against the heteropolysaccharide-containing glycopeptides isolated from TBM, that is, against the noncollagenous polypeptides of the TBM antigens. Anti-TBM antibodies were sought in the sera of 52 normal blood donors and of 11 patients presenting with glomerulonephritis and linear deposits of immunoglobulins. The average percentage (+/- 1 SD) of labeled TBM antigens precipitated in the serum of normal blood donors was 7.1 +/- 1.2. Of the patients presenting with glomerulonephritis and linear deposits along the GBM, 9 out of 11 exhibited anti-TBM antibodies by radioimmunoassay; among these 9 patients, 8 also displayed linear deposits of IgG along the TBM. Absorption of anti-TBM and anti-GMB antibodies with particulate TBM or GBM, with both types of glycopeptides isolated from GBM or TBM, indicated that the anti-TBM antibodies were directed against the noncollagenous polypeptides of TBM but that the anti-GBM antibodies mainly reacted with the collagenous polypeptides of TBM and GBM. Finally, it was found that the sera of 2 patients out of 15 presenting with lupus nephritis contained a significant anti-TBM-binding activity, mainly directed against the noncollagenous material of TBM.
Kidney Int 1978 Dec
PMID:Radioimmunologic method for detection of antitubular basement membrane antibodies. 74 71

Cell lines have been developed in Brown Norway rats from 3 primary uroepithelial tumors and from 2 in vivo transplanted uroepithelial tumors. After sc injection, cells of all cell lines gave rise to progressively growing tumors that eventually kill the host.
Natl Cancer Inst Monogr 1978 Dec
PMID:Spontaneous urinary bladder and ureter tumors in the Brown Norway rat. 74 84

In a multidimensional contingency table strategies have been proposed to build log-linear models using either stepwise methods or standardized estimates of the parameters of the saturated model. Brown (1976) proposed a two-step procedure to screen effects and then test a subset of models. Alternate methods of model building are discussed with respect to the final choice of model and with respect to intermediate information available to the data analyst during the selection process.
Biometrics 1978 Dec
PMID:Strategies for the selection of log-linear models. 74 51

The crystal structure has been determined of the anti-cancer drug daunomycin, as the hydrochloride monohydrate pyridine salt. The overall structure, previously determined by X-ray analysis of an N-bromoacetyl derivative (Anguili, R., Foresti, E., Riva Di Sanserverino, L., Isaacs, N.W., Kennard, O., Motherwell, W.D.S., Wampler, D.L. and Arcamone, F. (1971) Nat. New Biol. 234, 78-80) has been confirmed, although substantial conformational differences are observed. The conformation described here is very similar to that found for the related drug carminomycin I (Wani, M.C., Taylor, H.L., Wall, M.E., McPhaill, A.T. and Onan, K.D. (1975) J. Am. Chem. Soc. 97, 5955-5956; Pettit, G.R., Einck, J.J., Herald, C.L., Ode, R.H. Von Dreele, R.B., Brown, P., Brazhnikova, M.G. and Gause, G.F. (1975) J. Am. Chem. Soc. 97, 7387-7388); it is suggested that this represents a significantly stable molecular conformation; an intramolecular C(7)...O(9) hydrogen bond is invoked to account for this. This conformation is likely to be at least close to that of daunomycin when bound to DNA.
Biochim Biophys Acta 1977 Dec 14
PMID:Nucleic acid binding drugs. Part IV. The crystal structure of the anti-cancer agent daunomycin. 92 13

Two-word utterances of four language-impaired children at Brown's Stage I level of linguistic development were compared with two-word utterances of four young normal children at the same linguistic level to determine any differences between the two groups in the use of a set of 10 basic semantic relations. Type-token ratios for each semantic relation were used to compare use of semantic relations between groups. A significant difference was obtained for only one relation, with the language-impaired group demonstrating greater diversity in the use of the introducer + entity relation than the normal group. The findings indicated that at Stage I level of linguistic development, the language-impaired children demonstrated a linguistic system no different than the system of normal Stage I children. The findings are discussed relative to possible cognitive and linguistic strategies involved in language acquisition. It is suggested that some language-impaired children rather than being deficient in their ability to understand and code the basic semantic relations demonstrate a deficit in the higher, more complex aspects of the linguistic coding system.
J Speech Hear Res 1976 Dec
PMID:Semantic relations used by normal and language-impaired children at stage I. 100 56


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