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Biomedical subjects

C Y Yang

Publications and source records attributed to C Y Yang.

At least 307 records · Page 17Linked to original sources
PubMed1981

[Chromatography and rechromatography in high-performance liquid chromatography of peptide mixtures: the complete primary structure of an immunoglobulin L-chain of kappa-type, subgroup I (Bence-Jones Protein Den) (author's transl)].

In continuation of our work on the separation of enzymatic hydrolysates by high-pressure liquid chromatography with reverse-phases we present two new buffer systems: firstly 0.005M potassium phosphate, pH 6.0 and secondly aqueous trifluoroacetic acid, pH 2.15. As organic solvent acetonitrile is always used. The excellent properties are demonstrated by the separation of the tryptic peptides of Bence-Jones protein Den (Mr = 23000). Like ammoniumacetate these buffers are well suited for the first separation of peptide mixtures but can be used rather effectively in rechromatographies. If peaks are not or not fully resolved during the first chromatography they can be separated by a rechromatography in one of the other systems. This was most successful since in both cases the same high resolving technique is employed. From the primary separation 14 peptides could be isolated in analytically pure form. The remaining fragments were completely purified after one rechromatography. The amino acid analysis yielded also integer numbers and by a modified Edman degradation the primary structure could be determined. As with protein Wes (Kratzin, H., Yang, C.Y., Krusche, T.U. & Hilschmann, N. (1980) Hoppe-Seyler's Z. Physiol. Chem. 361, 1591--1598) all the peptides were recovered after high-pressure liquid chromatography, none was missing. From these data and from homology reasons the complete amino acid sequence of protein Den could be established. It contains 214 residues and belongs to subgroup I of the kappa-chains. The valine residue in position 191 indicates that it belongs to allotype Inv b+.

Amino Acid Sequence↗
PubMed1981

[Primary structure of class II human histocompatibility antigens. 1st communication. Amino acid sequence of the N-terminal 198 residues of the beta chain of a HLA-Dw2,2;DR2,2-alloantigen (author's transl)].

The beta-chains of HLA-D/DR antigens from a lymphoblastoid homozygous cell line (HLA-A3,3;B7,7;-Dw2,2;DR2,2) were purified by an exclusively chemical three step procedure: 1) Nonidet P-40/CM-cellulose ion-exchange-, 2) Na-dodecyl sulfate/sephacryl S-300- and 3) Na-dodecyl sulfate/hydroxylapatite chromatography. The amino acid sequence of the beta chain was established up to position 198. These residues comprise the extra-cellular part of the molecule which consists of two domains each probably containing a disulfide bridge, like immunoglobulin L chains. Within the first domain the carbohydrate moiety is attached to asparagine in position 19. Sequence work was hampered by the fact that the beta chain preparation of the HLA-Dw2,2;DR2,2 antigen actually consists of a pool of beta chains. The beta chain, the sequence of which has now been established, represents about 70% of the beta chain pool. The remaining 30% consist of at least 6 more chains which are homologous among one another as well as to the described beta chain. Since the antigens were gained from a homozygous lymphoblastoid cell-line our results indicate that the HLA-D region codes for at least 7 beta-chains and must therefore consist of a cluster of beta chain genes.

Amino Acid Sequence↗
PubMed1980

[Preparative separation of the tryptic hydrolysate of a protein by high-pressure liquid chromatography. The primary structure of a monoclonal L-chain of k-type, subgroup I (Bence-Jones Protein Wes) (author's transl)].

The tryptic hydrolysate of Bence-Jones protein Wes (Mr = 23000) was separated by high-pressure liquid chromatography in a volatile buffer system on a reversed-phase column. From the resulting 22 peptides 18 yielded integer numbers after amino acid analysis. They could be used directly for a modified Edman degradation. Two peptides were not separated by this procedure, two were missing. Under different conditions these four peptides could also be prepared in pure form. 3 mg was sufficient to elucidate the primary structure of the variable part of this protein completely. The arrangement of the tryptic peptides was deduced by homology to other k=chains. Protein Wes contains 214 residues and belongs to subgroup I of the k-chains. The valine residue in position 191 indicates that it belongs to allotype Inv b+.

Bence Jones Protein↗
PubMed1975

Studies of trachoma in families on Taiwan.

This study was undertaken to clarify the natural history and pathogenesis of trachoma. A group of families who live in a formerly trachoma hyperendemic area of Southern Taiwan were placed under continuous surveillance. The development in recent years of the micro immunofluorescence test for trachoma antibody, along with improved cell culture isolation methods, have allowed this surveillance to include repeated effective laboratory studies in addition to clinical observations. After four years' study of one group of families and three years of another, a number of interesting findings have been obtained. Evidence is presented supporting our hypothesis that trachoma is a disease of immumopathology and results from repeated reinfections with the trachoma organisms. The clinical findings of papillae, especially those of an acute nature, has been the clinical finding most closely associated with the isolation of the organism and the demonstration of antibody. Evidence is presented that transmission of the organism is usually within the family group. Although only trachoma immunotypes B and C previously had been associated with trachoma infection on Taiwan, data is presented from one family in which type D infections occurred. While a series of new and reinfections with trachoma organisms were demonstrated in some of the families under observation, the majority of the families not only showed no new infections but showed spontaneous healing or disappearance of clinical and laboratory evidence of trachoma infection. This tendency of active trachoma infection to disappear from a family in the absence of transmission of the organism parallels the rapid fall and prevalence of active trachoma on Taiwan during the past decade.

Adolescent↗
PubMed1972

Comparative studies on the detoxification of aflatoxins by sodium hypochlorite and commercial bleaches.

Cultures of Aspergillus flavus and aflatoxins were destroyed by a commercial bleach (Clorox; active ingredient, NaOCl) or analytical reagent grade NaOCl at 7.0 x 10(-3) M NaOCl in 5 days. Addition of Clorox or NaOCl at 2.8 x 10(-3) M to the fungal growth medium prior to inoculation completely inhibited the fungal growth. Aflatoxin production was inversely proportional to the logarithm of NaOCl concentration and time of treatment. Clorox and NaOCl were equally effective on aflatoxins, but fungal cells were lysed more readily by Clorox than by NaOCl. Mycelia older than 8 days lysed more readily than younger ones. Most conidia survived concentrations below 1.4 x 10(-3) M. The lowest effective concentration for a 2-hr treatment was 8.8 x 10(-3) M which is well below the Clorox concentration recommended for routine laboratory decontamination of aflatoxins. Mice and rats injected with aflatoxins and aflatoxins incompletely destroyed by Clorox died within 72 hr and had typical liver and kidney damage caused by aflatoxins. However, animals injected with NaOCl or Clorox or Clorox-destroyed aflatoxin extracts survived and showed no obvious liver or kidney damage.

Aflatoxins↗
PubMed1971

Clinical evaluation of the Taiwan trachoma control programme.

Following a clinical trial in 1959-60 and a prevalence survey in 1960-61, a community-wide trachoma treatment programme was instituted in Taiwan. A reexamination in 1968-69 of a subsample of the localities included in the 1960-61 survey provided the basis for a clinical evaluation of the programme.Except in areas of very high endemicity in 1960-61, trachoma appears to have ceased to be, or is in the process of ceasing to be, an important public health problem. A reduction in the number of cases that were active in 1960-61 has since resulted in reducing both the incidence and the severity of the disease. Cases showing signs of past experience of the disease (healed cases), as well as cases with grave irreversible sequelae or complications, belong to the pretreatment cohort and are moving along "time" without being replaced.In communities with an initially very high endemicity it is open to question whether the incidence of the disease has been reduced to the level at which it will fail to perpetuate itself. The results of a very limited survey conducted in 1970 are encouraging: a repeat sample survey is planned for 1972.

Adolescent↗