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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Large fragments of human serum albumin were produced by treatment of the native protein with pepsin at pH3.5. Published sequences of human albumin [Behrens, Spiekerman & Brown (1975) Fed. Proc. Fed. Am. Soc. Exp. Biol. 34, 591; Meloun, Moravek & Kostka (1975) FEBSLett.58, 134-137]were used to locate the fragments in the primary structure. The fragments support both the sequence and proposed disulphide-linkage pattern (Behrens et al., 1975). As the pH of a solution of albumin is lowered from pH4 to pH3.5, the protein undergoes a reversible conformational change known as the N-F transition. The distribution of large fragments of human albumin digested with pepsin in the above pH region was critically dependent on pH. It appeared that this distribution was dependent on the conformation of the protein at low pH, rather than the activity of pepsin. The yields of the large fragments produced by peptic digestion at different values of pH suggested that the C-terminal region of albumin unfolds or separates from the rest of the molecule during the N-F transition. The similarity of peptic fragments of human and bovine albumin produced under identical conditions supports the proposed similar tertiary structure of these molecules.
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PMID:Large fragments of human serum albumin. 1 51

Primary segmental demyelination accompanied by mononuclear phagocytes was induced by injection of antiserum into rat peripheral nerve, and the morphologic sequence of events was studied. Antisera were obtained from rabbits with experimental allergic neuritis (EAN) produced by the inoculation of emulsified bovine peripheral nerves in complete Freund's adjuvant. Sera were injected directly into rat sciatic nerve to circumvent the blood-nerve barrier. Recipient rats developed sensorimotor paralysis on the side injected with experimental allergic neuritis sera. Intense focal demyelinative lesions resulted from injection of experimental allergic neuritis sera. Control sera obtained from rabbits inoculated with bovine serum albumin in complete Freund's adjuvant did not produce paralysis or demyelination. The earliest change was damage to Schwann cells, seen 20 minutes after antiserum injection. Within a few hours lamellar splitting and vacuolation of myelin began to paranodal regions and Schmidt-Lanterman clefts and there were infiltrating polymorphonuclear cells. By 8 hours without the detectable presence of monocytes or macrophages, myelin vesiculation became advanced and widespread. By 15 hours, endoneurial edema had reached its maximum. Macrophages were found in association with myelinated nerve fibers. From that time through the next 5 days, demyelination progressed to complete denudation of axons by macrophage phagocytosis of myelin. Activated cytoplasm of Schwann cells reinvested demyelinated axons, often in concert with persisting phagocytic macrophages. Peripheral nerve demyelination thus transferred evolved rapidly, and myelin destruction occurred prior to the appearance of monocytes or macrophages. Demyelinating activity was lost after absorption by purified peripheral nerve myelin but not by liver or kidney and was heat-labile and complement dependent (T. Saida, K. Saida, D. H. Silberberg, and M. J. Brown: Nature 272: 639, 1978).
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PMID:Antiserum-mediated demyelination in vivo: a sequential study using intraneural injection of experimental allergic neuritis serum. 73 72

We describe a convenient and specific radioimmunoassay for urinary metanephrine, in which we used an antiserum generated in rabbits by injecting with synephrine conjugated to bovine serum albumin as described by Grota and Brown [Endocrinology 98, 615 (1976)]. The antiserum is specific for metanephrine and epinephrine. Epinephrine cross reaction is minimized to 1% by adding 2 ng of epinephrine to each assay tube. Incubation time is 12 h. The sensitivity of the assay is 40 pg. Within-and between-assay coefficients of variation are 7.0 and 9.7%, respectively. We assayed first-voided morning urine and 24-h urine specimens from 15 normal subjects before and after acid hydrolysis, to assess total and free metanephrine concentrations. Mean (+/-SD) total and free urinary metanephrine excretion were 17 +/- 11 and 3.5 +/- 1.0 micrograms/24 h in these subjects; corresponding values for the morning specimens were 13.4 +/- 8.3 and 3.5 +/- 1.5 micrograms/liter, respectively.
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PMID:Radioimmunoassay for free and conjugated urinary metanephrine. 87 72

Several fragments of bovine serum albumin have been isolated following limited tryptic hydrolysis and their positions then determined in the bovine serum albumin sequence published by J. R. Brown ((1975), Fed. Proc., Fed. Am. Soc. Exp. Biol. 34, 591). When bovine serum albumin was coupled to palmityl-aminoethylamino-agarose and digested with trypsin, two fragments were obtained: (a) peptide 115-184, containing the highly aromatic disulfide loop 3 of Brown's model, and (b) a larger fragment, residues 377-581, containing disulfide loops 7-9. This fragment constitutes the third of the three domains of the albumin molecule. From bovine serum albumin digested in solution, peptide 115-184 was again obtained, as well as (c) a 39,000-dalton fragment identified as residues 198-581, loops 4-9 of the second and third domains, but with a long, tryptophan-containing segment 204-238 missing from loop 4. The ability to isolate these fragments without cleaving disulfide bridges is partial confirmation of the proposed model of bovine serum albumin as a series of nine independent loops.
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PMID:Fragments of bovine serum albumin produced by limited proteolysis. Isolation and characterization of tryptic fragments. 109 43

Five new fragments of bovine serum albumin have been isolated following limited peptic hydrolysis. These fragments, and the two peptic fragments previously described by King (King, T.P. (1973), Arch. Biochem. Biophys. 156, 509), were positioned within the albumin sequence published by Brown (Brown, J.R. (1975), Fed. Proc., Fed. Am. Soc. Exp. Biol. 34, 591) on the basis of molecular weight, amino acid composition, and amino- and carboxyl-terminal sequences. The fragments correspond to residues 1-385, 1-306, 307-581, 49-185, 186-306, 307-385, and 353-503 in the albumin sequence. These peptides are likely to be native in structure since disulfide bonds were not cleaved during their preparation. In each case the amino acid composition and terminal sequences have confirmed the bovine serum albumin sequence and disulfide bridging pattern proposed by Brown, and the offer further proof that bovine albumin is composed of a series of nine independent loops. These fragments should be useful in elucidating the structure-function relationships of albumin.
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PMID:Fragments of bovine serum albumin produced by limited proteolysis. Isolation and characterization of peptic fragments. 110 Jan 6

Brown-Norway rats (male) were sensitized with both dinitrophenylated-bovine serum albumin (DNP-BSA) and Bordetella pertussis simultaneously in order to induce airway hyperresponsiveness (AHR) as the first sensitization. At five days, DNP-BSA was inhaled as a booster into the airways under thiopental anaesthesia. At eight days, inhalation of antigen markedly increased the tracheal pressure (TP) in sensitized rats (11.9 +/- 1.6 cmH2O) and slightly increased TP in non-sensitized rats (1.1 +/- 0.4), the difference between the two groups being significant (p less than 0.001). Twenty-four hours after antigen challenge, the airway responsiveness to ACh in sensitized rats was markedly increased to about 4-fold as compared to that in non-sensitized rats. Inhalation of dinitrophenylated-ovalbumin failed to increase the airway responsiveness to ACh in rats sensitized with DNP-BSA, although a marked increase in TP was induced immediately after antigen challenge. We thus succeeded in preparing a model of AHR by employing a new procedure of sensitization.
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PMID:Induction of airway hyperresponsiveness in allergic rats. 171 32

Brown-Norway (BN) rats were sensitized by 3 aerosol exposures to ovalbumin (OA; 10 mg/ml) at days 1, 3 and 14. At day 21, the rats were challenged with the antigen or vehicle by aerosol. Alveolar macrophages (AM) were obtained by bronchoalveolar lavage and the expression of Fc epsilon RII/CD23 was assessed by flow cytometry after staining with the BB10 monoclonal antibody. A maximum of 74% of the AM from sensitized and challenged BN rats expressed FC epsilon RII/CD23 24 h after OA exposure, compared to 12% of the cells from rats exposed to vehicle. Sprague-Dawley rats were passively sensitized by intravenous injection of 0.1 or 0.05 ml/kg mouse ascitic fluid containing dinitrophenyl (DNP)-specific monoclonal IgE (2682-1) and after 24 h exposed to an aerosol of 5 mg/ml of DNP-bovine serum albumin for 30 min. In this case also, antigen exposure induced the expression of Fc epsilon RII/CD23 on 75% AM, compared to 17% AM from saline-challenged rats. Such an induction of Fc epsilon RII/CD23 on AM was, however, not observed when the animals were challenged with either histamine, serotonin or acetylcholine by aerosol. The antigen-induced expression of Fc epsilon RII/CD23 on AM was inhibited upon treatment of the rats with ketotifen or beclomethasone. In addition, oral or aerosol administration of respectively BN 50730 or BN 52021 (two structurally unrelated platelet-activating factor antagonists), inhibited the antigen-induced Fc epsilon RII/CD23 expression on AM, indicating the participation of this lipid mediator in this process.
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PMID:Pharmacological modulation of the antigen-induced expression of the low-affinity IgE receptor (Fc epsilon RII/CD23) on rat alveolar macrophages. 183 81

We have extended our earlier work (C.F. Beaulieu, J.I. Clark, R.D. Brown III, M. Spiller, and S.H. Koenig, Magn. Reson. Med. 8, 45 (1988] on the magnetic field dependence of 1/T1 (NMRD profiles) of calf lens nuclear homogenates, at 25 degrees C, to 5 degrees C, and to other protein systems as well. These include concentrated solutions of myoglobin and bovine serum albumin, both globular proteins, the first compact and roughly spherical, the other extended, flexible, and with weak internal bonding; chicken lens homogenate, for which the dominant crystallins (lens proteins) are approximately 70% alpha-helical compared with calf crystallins, which are essentially all beta-sheet; and hen egg white, both native and heat-denatured. Our earlier conjectures regarding a reversible change in protein organization of the calf lens crystallins as a function of solute protein concentration is given added support. Our findings suggest that cytoplasmic homogenate can be characterized as a heterogeneous and polymorphic solution of crystallins. At high concentrations the NH moieties of the protein backbone become accessible to solvent with water (not NH proton) exchange rates greater than 10(4) s-1. This conclusion is based on two aspects of the observed NMRD profiles. At low crystallin concentration, the profiles of calf and chicken lens homogenates are similar in form to those of myoglobin and native hen egg white, a form that has been studied previously for a range of diamagnetic globular proteins and has been demonstrated to arise from the rotational thermal motion of the solute molecules. At high crystallin concentrations, the NMRD profiles of the lens homogenates develop a monotonic background (high rates at low fields), much like that of the heat-denatured egg-white sample and those of most tissues. In addition, there is a set of peaks in the central part of the profiles of the concentrated crystallins, seen also in the denatured egg white and some tissues but not in the myoglobin sample, which is known to arise from cross-relaxation interactions between the water protons and (through the intermediary of the NH proton) the 14N quadrupolar levels. The magnitude of these peaks, which is larger by an order of magnitude for native calf lens homogenates than for any tissue, requires that the majority of the NH moieties be accessible to water. Finally, going to 5 degrees C for the native calf lens homogenate takes the sample below the temperature of reversible phase separation, and it becomes opaque.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Relaxometry of lens homogenates. II. Temperature dependence and comparison with other proteins. 273 92

Sensitive and specific radioimmunoassays of metanephrine and normetanephrine were developed by use of 125I-labeled synephrine and specific metanephrine antibody, and 125I-labeled octopamine and specific normetanephrine antibody. Specific antibody for both metanephrine and normetanephrine was raised in rabbits by immunization with bovine serum albumin conjugated with the corresponding hapten, prepared by the method of Grota and Brown (Endocrinology 1976;98:615). The detection limits of the metanephrine and the normetanephrine radioimmunoassays were 2 and 6 pg/tube, respectively. Mean plasma metanephrine and normetanephrine values for 24 normal subjects were 62 (SD 14) and 100 (SD 40) ng/L, respectively. Mean urinary metanephrine and normetanephrine values for 22 normal subjects were 154 (SD 74) and 217 (SD 109) micrograms/day. For 14 pheochromocytoma patients, plasma metanephrine and normetanephrine values ranged from 29 to 683 and from 28 to 7850 ng/L, and urinary metanephrine and normetanephrine values were 606 to 6630 and 296 to 4800 micrograms/day, respectively. The present methods are simple and suitable for routine tests or for mass screening for pheochromocytoma.
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PMID:Radioimmunoassay of metanephrine and normetanephrine for diagnosis of pheochromocytoma. 309 20

Concerning small-bowel transplantation in children, the question arises whether a segmental small-bowel graft from an adult donor would permit normal growth of the young recipient. Orthotopic small-bowel transplantation was performed in 4- to 6-week-old Lewis rats weighing 100-135 g. The entire small bowel of the recipient was replaced with an intestinal allograft consisting of the entire small bowel (N = 6), the jejunum (N = 6), or the ileum (N = 6) from adult Brown Norway rats. Immunosuppression with cyclosporine (15 mg/kg im) on alternate days for 4 weeks achieved graft acceptance of indefinite duration. Six and twelve months after transplantation, all recipients demonstrated normal global nutritional parameters (hematocrit, serum albumin) and gained weight at a rate comparable to that for age-matched controls. Nutritional deficiencies did not become apparent clinically. By 10 to 12 months, the levels of fat-soluble vitamins (A and E) were reduced significantly in recipients of segmental grafts. Vitamin B12 levels were also reduced but not significantly. Fecal fat was significantly elevated in all rats with grafts (3.2 +/- 1.0 to 4.8 +/- 0.9 g fat/100 g stool; controls, 1.8 +/- 0.4), but the increase was most pronounced in those with jejunal grafts (4.7 +/- 0.9). This was paralleled by a reduction in serum triglyceride levels in all transplanted rats, a reduction which reverted to normal by 10 to 12 months for rats with entire small-bowel grafts but not for those with segmental grafts. Graft biopsy demonstrated normal intestinal architecture with villus hyperplasia of segmental grafts.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Recipient growth and nutritional status following transplantation of segmental small-bowel allografts. 349 94


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