The Chemistry of Keratins

Crewther, W.G.; Fraser, R.D.B.; Lennox, F. G.; Lindley, H.

doi:10.1016/s0065-3233(08)60390-3

Cited by 275 publications

(134 citation statements)

References 517 publications

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“…The reduction in the concentration of some essential amino acids in plasma (valine, leucine, and isoleucine) with infusions of either methionine or cystine is consistent with the expected effects of supplying a limiting amino acid, and may indicate that the utilization of these amino acids for the synthesis of wool or tissue proteins was stimulated by supplying methionine or cystine. Because wool proteins contain very little methionine (Crewther et al 1965), methionine may stimulate wool growth mainly by supplying cyst(e)ine, and either amino acid may be regarded as limiting for wool growth. With large amounts of methionine infused into the abomasum, although utilization of amino acids for wool growth, as discussed above, would be depressed, the utilization of amino acids for body weight gain would be stimulated (Reis 1967).…”

Section: Discussionmentioning

confidence: 99%

Plasma Amino Acid Patterns in Sheep Receiving Abomasal Infusions of Methionine and Cystine

Reis¹,

Tunks²,

Sharry³

1973

Aust. Jnl. Of Bio. Sci.

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Plasma amino acid patterns were studied in sheep receiving varying amounts of DL-or L-methionine (0'6-10·0 g/day) or L-cystine (2·0 and 8·0 g/day) as abomasal supplements or DL-methionine (10 g/day) as a dietary supplement.Total amino acids in plasma decreased when small amounts (0'6-2'5 g/day) of methionine were infused, but increased substantially with the larger amounts of methionine (4'9-10·0 g/day). However, when methionine and taurine were excluded, the remaining amino acids decreased with all amounts of methionine. Cystine supplementation caused smaller changes in total amino acids.Methionine infusions significantly increased the concentration of methionine, cystine, taurine, and cystathionine in plasma. Cystine infusions increased the concention of the latter three compounds, but not that of methionine. Infusion of small amounts of methionine (0· 6-2 . 5 g/ day) produced only small increases in plasma methionine; with the infusion of larger amounts plasma methionine increased rapidly. The relationship between plasma methionine and amount of methionine infused was described by two straight lines which intersected at about 3 . 3 g/ day of methionine. With an infusion of 10 g/day the mean plasma methionine concentration was 235 ",moles/ 100 ml, which represented 64% of the total plasma amino acids. In contrast, an equimolar amount of cystine (8 g/day) produced only a small increase in plasma cystine, and had no effect on plasma methionine.Infusions of both methionine and cystine caused considerable reductions in the plasma concentrations of the branched-chain amino acids (valine, leucine, and isoleucine), and of serine and glycine.Dietary supplements of methionine (10 g/day) caused no change in the total concentration of amino acids in plasma nor in the concentration of any individual amino acid.

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Section: Discussionmentioning

confidence: 99%

Plasma Amino Acid Patterns in Sheep Receiving Abomasal Infusions of Methionine and Cystine

Reis¹,

Tunks²,

Sharry³

1973

Aust. Jnl. Of Bio. Sci.

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“…All tumors were well differentiated and typical for verrucous squamous cell carcinoma of the bladder (2). Four of the tumors were of stage 1 or 2, and 19 tumors were of stage 3 for our studies as judged from hematoxylin-eosin stained 5 pm sections adjacent to the sections which were prepared for flow cytometric analysis.…”

Section: Methodsmentioning

confidence: 99%

Improved method for release of cell nuclei from paraffin‐embedded cell material of squamous cell carcinomas

et al. 1993

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An improved method of releasing cell nuclei from paraffin-embedded highly keratinized squamous cell carcinomas by pretreatment with 85% formic acid-0.3% H,O, followed by enzymatic treatment with subtilisin Carlsberg is described. After DAPI staining the resulting suspensions of cell nuclei were analyzed by DNA flow cytometry, in addition to microscopy. The total yield of released cell nuclei was improved and the proportion of tumor cell nuclei in the suspensions increased from 12% to 53% using this method compared to the conventional preparation technique. Cytoplasmic residue disappeared nearly completely. Thus, the finding of false aneuploid cell populations representing diploid cells with autofluorescent cytoplasm could be avoided. In addition, even small true aneuploid cell populations could be detected due to the increased proportion of released tumor cell nuclei and the lower proportion of background in the >2C region. 0 1993 Wiley-Liss, Inc.Key terms: DNA flow cytometry, keratinized tissues, archival material, formic acid-H202In 1983 Hedley et al. (4) introduced a technique for preparation of cell nuclei from paraffin-embedded tissues for flow cytometric DNA measurement. This method has been widely used for retrospective analyses of the cellular DNA content in various types of malignancies. The original Hedley method has recently been modified using subtilisin Carlsberg (Sigma, protease XXIV) instead of pepsin and avoiding all centrifugation steps. By this means, cell loss and clumping of the cell nuclei or the debris were minimized, also resulting in a better estimate of the proportion of cells in various parts of the cell cycle (5). This improved method, in our hands, gave good results in archival material from various tumors: adenocarcinomas of the prostate, colonrectum, and urinary bladder; transitional cell carcinomas of the bladder; carcinomas of the testis and ovary, and myosarcomas of the uterus. However, we failed to adapt this method in verrucous squamous cell carcinoma of the Bilharzial bladder. The problem was the low yield of cell nuclei from the tumors and remaining fluorescent cytoplasm. This problem has also been observed by others in melanotic lesions of the skin (7). In order to increase the release of bare cell nuclei from the tissue sections by proteolytic treatment, the tissue pieces were, prior to this treatment, incubated with formic acid and HzOz, which dissolves disulfide bonds of keratins. The results obtained by this procedure were compared with the results obtained by the conventional method, which omits cleavage of disulfide bonds. MATERIAL AND METHODSCell Material Tissue samples from 23 patients who underwent radical cystectomy for invasive verrucous carcinomas of the bladder at the Urology and Neuphrology Center of Mansoura, Egypt were studied. All tumors were well differentiated and typical for verrucous squamous cell carcinoma of the bladder (2). Four of the tumors were of stage 1 or 2, and 19 tumors were of stage 3 or 4 according to the classification of the UICC (6). Area...

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“…A very large amount of work has been done over many years on the development of methods, which are relatively mild and (hopefully) specific, for the scission of a particular type of bond in the three-dimensional protein network of keratin fibres (reviewed by Crewther et al 1965a). By this me(tns solubilization of the bulk of the proteins in the keratin are achieved.…”

Section: Introductionmentioning

confidence: 99%

Keratin Fibres VII. Proteins of the Histological Components of Kangaroo Fibres

Bradbury¹,

O'shea²

1972

Aust. Jnl. Of Bio. Sci.

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Cortical cells, cuticle, and an impure sample of medulla were prepared from kangaroo fibres by vigorous agitation in formic acid at room temperatme, which control experiments show causes no degradation of soluble. high-or low-sulphur proteins. Many reductive extraction procedures were examined and the best method appears to be treatment with O· 2M thioglycollate at pH 11· 0 in 8M urea for 3 hr at 40°C, followed by coupling with iodoacetate. The high-and low-sulphur proteins from kangaroo fibres and its histological components were prepared and examined by gel filtration using Agarose in 8M urea at pH 8 with a column calibrated for measurement of molecular weight.The amount of protein extracted by thioglycollate from kangaroo fibres (57%) is less than that from wool because of the presence of non-extractable medulla in the former case. The 42% of soluble protein extracted from cuticle by thioglycollate does not contain low-sulphur proteins and most of the high-sulphur proteins have molecular weights < 12,500. The high-sulphur proteins of molecular weight range 15,000-30,000 and the low-sulphur proteins of molecular weight range 40,000-70,000 from kangaroo fibres arise almost entirely from the 'cortical cells. The proteins which are rich in glycine and aromatic amino acids originate from the cortical cells of kangaroo fibres. In wool, the bulk of these proteins are from the microfibril-matrix structure of the cortical cells and a small fraction from the cell membrane complex.

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The Chemistry of Keratins

Cited by 275 publications

References 517 publications

Plasma Amino Acid Patterns in Sheep Receiving Abomasal Infusions of Methionine and Cystine

Plasma Amino Acid Patterns in Sheep Receiving Abomasal Infusions of Methionine and Cystine

Improved method for release of cell nuclei from paraffin‐embedded cell material of squamous cell carcinomas

Keratin Fibres VII. Proteins of the Histological Components of Kangaroo Fibres

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