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Biomedical subjects

C H Chou

Publications and source records attributed to C H Chou.

At least 91 records · Page 5Linked to original sources
PubMed1983

Epitopes of peptide 43-88 of guinea pig myelin basic protein: localization with monoclonal antibodies.

Two monoclonal antibodies, one raised by immunization with mouse myelin basic protein (MBP) and the second raised by immunization with peptide 68-88 of guinea pig MBP, were compared with respect to specificity. The former antibody (15.32) cross-reacted completely with rat, guinea pig, human, and bovine MBP. It also reacted with peptide 43-88 from each MBP. The latter antibody (22.17) was nonreactive with MBP, but cross-reacted with peptide 43-88 from rat, human, guinea pig, and bovine MBP. When tested with small peptides derived from peptide 43-88, antibody 22.17 reacted with an epitope in the C-terminal region. Antibody 15.32 reacted with an epitope in the N-terminal half of the peptide. The data show that 22.17 reacted with a unique epitope associated only with free peptide, whereas 15.32 recognized an epitope common to both peptide 43-88 and MBP.

Animals↗
PubMed1983

Encephalitogenic activity of the small form of mouse myelin basic protein in the SJL/J mouse.

Mouse myelin basic proteins (MBP) were prepared by ion-exchange chromatography of an acid extract of homogenized, delipidated mouse brain. The use of a linear salt gradient during ion-exchange chromatography gave three peaks, 1, 2, and 3, of MBP. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis of these peaks showed that peaks 2 and 3 were a mixture of the large and small forms of mouse MBP, whereas peak 1 was solely the small form. Tryptic peptides of mouse and rat small form MBP were compared by high-performance liquid chromatography. The elution times and absorbances at 210 nm were identical for 16 of 21 peaks derived from small form MBP of the two species. Amino acid analysis showed that 10 corresponding peaks from the small form of mouse and rat MBP had identical amino acid composition. When tested for encephalitogenicity in SJL/J mice, both the mixture of large and small forms of mouse MBP and the small form mouse MBP were highly encephalitogenic.

Amino Acid Sequence↗
PubMed1982

Basic protein in brain myelin is phosphorylated by endogenous phospholipid-sensitive Ca2+-dependent protein kinase.

Phosphorylation of myelin basic protein (MBP) in rat or rabbit brain myelin was markedly stimulated by Ca2+, and this reaction was not essentially augmented by exogenous phosphatidylserine or calmodulin or both. Solubilization of myelin with 0.4% Triton X-100 plus 4 mM EGTA, with or without further fractionation, showed that Ca2+-dependent phosphorylation of MBP required phosphatidylserine, but not calmodulin. DEAE-cellulose chromatography of solubilized myelin revealed a pronounced peak of protein kinase activity stimulated by a combination of Ca2+ and phosphatidylserine; a protein kinase stimulated by Ca2+ plus calmodulin was not detected. These findings clearly indicate an involvement of phospholipid-sensitive Ca2+-dependent protein kinase in phosphorylation of brain MBP, although a possible role for the calmodulin-sensitive species of Ca2+-dependent protein kinase in this reaction could not be excluded or established. Phosphorylation of MBP in solubilized rat myelin catalyzed by the phospholipid-sensitive enzyme was inhibited by adriamycin, palmitoylcarnitine, trifluoperazine, melittin, polymyxin B, and N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7).

Animals↗
PubMed1982

Encephalitogenic activity of guinea pig myelin basic protein in the SJL mouse.

GPBP was shown to be encephalitogenic in SJL mice by direct challenge and in experiments in which an adoptive transfer system was employed. The three fragments obtained by treating GPBP with pepsin were assessed in the same manner. The encephalitogenic activity resided in the C terminal half of the molecule (residues 89-169). LNC also proliferated to the same fragment in vitro. Fragments 1-37, and, to a lesser extent, 44-48 stimulated sensitized LNC to proliferate but did not induce disease.

Amino Acid Sequence↗
PubMed1982

[Helminth and pinworm control for primary school and kindergarten children by periodical mass-examination and treatment in Suan-Yuan District, Taipei (author's transl)].

The mass pre-control survey was done in fall semester 1978 by both methods that Kato's thick smear for helminthic infection and cellophane tape perianal swab for pinworm infection. There are about 19,000 primary school children and around 5,000 kindergarten children in Suan-yuan District, being the subjects. The helminthic positive rates (%) obtained were 5.18 and 3.81, respectively. The rates for pinworm were found 28.68% former and 29.00% for the latter. Drug was given to the egg-positive persons after mass examination, in each semester, for three consecutive years. Two broad-spectrum anthelmintics, pyrantel pamoate and mebendazole were used. The children who harbored Ascaris, hookworm or pinworm were given pyrantel tablet as a single dose of 10 mg/kg body weight, and whipworm positives were given a standard course of 100 mg of mebendazole twice daily for three days. After three-year operation, in accordance with the results of examination in Spring semester 1981, the egg positive rates were sharply dropped to 0.56% for the primary school children and 0.50% for the kindergarten. The pinworm infection rates for the above-mentioned group were also reduced to 13.05% and 18.68%, respectively.

Child↗
PubMed1980

Prevention of experimental allergic encephalomyelitis in Lewis rats with peptide 68-88 of guinea pig myelin basic protein.

The highly encephalitogenic guinea pig peptide 68-88 has been used to develop an effective and reproducible model of protection in the Lewis rat. Doses as low as 0.1 nmol of peptide protected 70% of rats when injected intraperitoneally six and four weeks prior to challenge with 0.05 nmol of the peptide in complete Freund's adjuvant. Fragments derived from guinea pig peptide 68-88 by selective enzyme cleavage were then tested for their capacity to provide protection in this model system. These fragments had previously been well characterized both biochemically and immunologically. The protection provided by each fragment closely paralleled its capacity to induce disease. This suggests that the region of peptide 68-88 required for protection is similar to that needed for induction of experimental allergic encephalomyelitis and the other T-cell functions of the peptide. B-cells did not appear to participate; peptide 68-85, which has no capacity to produce antibody against peptide 68-88, gave full protection, while peptide 79-88, which contains the major B-cell determinant of the peptide, afforded no protection. Rat peptide 68-88 did not protect against challenge with the guinea pig peptide, demonstrating a critical role for serine 79. These studies support the concept that nonencephalitogenic agents do not protect against experimental allergic encephalomyelitis at doses comparable to those of encephalitogenic agents.

Animals↗
PubMed1979

The immune response of Lewis rats to peptide 68-88 of guinea pig myelin basic protein. I. T cell determinants.

A series of peptides, produced from peptide 68-88 by selective enzyme cleavage, were used to define the amino acid sequences required for the induction of experimental allergic encephalomyelitis (EAE), an in vitro lymphocyte proliferative response (LPR), and serum antibody by peptide 68-88 in the Lewis rat. Here we present data that indicate that the T cell determinants for induction of EAE, an LPR, and helper function in the production of antibody are located in the same region of the molecule and that a minimum of 13 amino acids are involved; i.e., residues 71-85.

Amino Acids↗
PubMed1979

The immune response of Lewis rats to peptide 68-88 of guinea pig myelin basic protein. II. B cell determinants.

A series of peptides, produced from peptide 68-88 by selective enzyme cleavage, were used to define the amino acid sequences reactive with Lewis rat anti-peptide 68-88 antibody. One hundred per cent of 38 rats immunized with peptide 68-88 recognized a B cell determinant residing in the region of residues 80-88. The three carboxy-terminal amino acids, residues 86-88, appeared to confer conformation on this determinant. In roughly two-thirds of the rats, the reactivity with this major B cell determinant was equal to the reactivity with the immunizing peptide. In these rats the anti-peptide 68-88 antibodies were of the IgG2 class. A third of the rats recognized an additional determinant(s) and in these the predominant class of antibody was IgG1.

Animals↗
PubMed1978

Specificity of antisera from Lewis rats immunized with encephalitogenic fragment 43-88 of guinea pig myelin basic protein.

Inbred Lewis rats were immunized with encephalitogenic fragment 43-88 of guinea pig myelin basic protein emulsified in complete Freund's adjuvant. After recovery from experimental allergic encephalomyelitis (EAE) the animals were given a booster immunization, bled, and the specificity of the individual anti-fragment antisera was examined by direct binding assays by using radioiodinated fragment 43-88 and peptides 43-67, 68-88, and 79-88. Competitive-binding experiments with these peptides in competition with labeled fragment 43-88 were also done. The results of these experiments indicated that the immunodominant region of fragments 43-88 was the carboxy-terminal half of the molecule. Individual antisera recognized different antigenic determinants within this region.

Animals↗
PubMed1977

Molecular internalization of a region of myelin basic protein.

The conformation of myelin encephalitogenic or basic protein (BP) was investigated with a double-antibody radioimmunoassay by studying the reaction of BP or its fragments with antibodies produced in two rabbits against peptide 43-88 linked to rabbit serum albumin. Both antisera reacted well with peptide 43-88 but showed little or no reaction with BP. Absorption of these antisera with a BP-immunoadsorbent did not remove the antibody activity against peptide 43-88. Within the region of peptide 43- 88 it was shown that peptides 68-88 and 79-88 gave an equivalent or better reaction than peptide 43-88, whereas peptides 43-67 and 64-73 had very little reactivity. In the BP fragments containing region 43-88, peptide 1-88 showed the best reactivity, peptide 20-166 showed minimal reactivity, while peptide 1-115 showed none. These data document the internal position of at least a portion of peptide 43-88 and all of residues 79-88 in the BP molecule. The much greater reactivity of peptide 1-88 as compared to peptide 1-115 suggests that the region or a portion of the region of BP containing residues 89- 115 participates in the conformational alignment of BP restricting access to peptide 79-88. After absorption with BP, neither of the antisera prepared to peptide 43-88 reacted with PNS myelin in fixed tissue sections but continued to react with CNS myelin in similarly treated sections. The present findings demonstrate the need to consider the role of shielded antigenic determinants in the investigation of antigens or of immune responses.

Animals↗
PubMed1977

Polydisperse particulate solids mixing and segregation: nonstationary Markov chains.

The feasibility of analyzing interparticulate translocations within agitated beds of polydisperse particulate solids in terms of Markov chains was investigated. A binary mixture of spherical particles subjected to vertical sine wave vibration is shown to behave in accordance with a nonstationary. Markov chain having singly stochastic transition matrixes. The transition probability elements of such matrixes, calculated from a knowledge of the initial and final occupancy vectors, agree with those estimated using tracer particles. With appropriate restrictions, the former method, based on the solution of simultaneous equations, permits a quantitative evaluation of particle mobilities throughout the bed.

Chemistry, Pharmaceutical↗
PubMed1977

Raman spectral studies of nucleic acids. XVII. Conformational structures of polyinosinic acid.

Laser-Raman spectra of poly(rI) show the formation of an ordered complex in aqueous solutions of high ionic strength. This structure exhibits the A-helix geometry, contains stacked bases and is apparently stabilized by specific hydrogen bonding involving hypoxanthine C6=0 groups. Thermal dissociation of the poly(rI) complex (Tm=45 degrees C) yields single-stranded and disordered poly (RI) chains. A disordered structure also occurs for poly (rI) in aqueous solutions of low ionic strength. In oriented films, poly (rI) forms an ordered structure probably the same as that which occurs in solutions of high ionic strength. Raman intensities measured at 815 and 1100 cm-1 in spectra of poly (rI) and poly (rU)-poly (rA)-poly(rU) indicate that the correlation previously established for single- and double-stranded ribopolymer structures is valid also for these multi-stranded structures. X-ray diffraction and model-building studies confirm the A-helix structure.

Deuterium↗