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Biomedical subjects

E Hannappel

Publications and source records attributed to E Hannappel.

At least 55 records · Page 3Linked to original sources
PubMed1988

Thymosin beta 4Xen: a new thymosin beta 4-like peptide in oocytes of Xenopus laevis.

Two new thymosin beta 4-like peptides have been detected in ovaries of Xenopus laevis and Rana esculenta. Previously, it was reported that thymosin beta 4 can be found in various species, from mammals to amphibians, e.g., in X. laevis [S. Erickson-Viitanen, S. Ruggieri, P. Natalini, and B.L. Horecker (1983) Arch. Biochem. Biophys. 221, 570-576]. However, oocytes and spleen from R. esculenta contain no thymosin beta 4 but a similar peptide without methionine. The peptide from R. esculenta elutes from a reversed-phase column about 5 min later than thymosin beta 4. The peptide from X. laevis, referred to as thymosin beta 4Xen, can hardly be distinguished from thymosin beta 4 by its retention time on HPLC, by amino acid analysis, its isoelectric point, or tryptic fingerprinting. Amino acid analyses of the tryptic fragments, however, have revealed that thymosin beta 4 and beta 4Xen are different. The amino acid sequence of thymosin beta 4Xen is reported. Thymosin beta 4 and beta 4Xen differ in the amino acid residues at positions 15, 40, and 41. At position 15 serine is replaced by alanine and at 41-42 the sequence is Thr-Ser instead of Ala-Gly. Depending on their size, defolliculated oocytes contain between 2.7 and 52.6 ng thymosin beta 4Xen which is comparable to the amount of histones in oocytes.

Amino Acid Sequence↗
PubMed1987

Determination of thymosin beta 4 in human blood cells and serum.

A simple one-step procedure for the determination of thymosin beta 4 in whole blood, various blood corpuscles, plasma and serum by reversed-phase high-performance liquid chromatography (HPLC) is described. The blood cells were isolated by a Ficoll density gradient technique. The isolated cells were lysed and deproteinized with perchloric acid in the presence of an internal standard. The supernatant solution was neutralized by potassium hydroxide solution and thymosin beta 4 was measured by HPLC without further manipulations. The following amounts (fg per cell) were determined: polymorphonuclear leukocytes (409), mononuclear leukocytes (267) and platelets (22.3). Erythrocytes contained no thymosin beta 4. The average concentration of thymosin beta 4 in an extract of whole blood was 16.3 micrograms/ml. The concentration in plasma was less than 1% of that value. However, if serum was prepared and not immediately removed from the clotted blood, the concentration of the peptide increased from 0.04 to 2.1 micrograms/ml within 24 h. The biological significance of the findings is discussed.

Adult↗
PubMed1986

One-step procedure for the determination of thymosin beta 4 in small tissue samples and its separation from other thymosin beta 4-like peptides by high-pressure liquid chromatography.

Thymosin beta 4 has been determined by a simple and fast one-step procedure in different tissues of rats. The tissues (1 to 40 mg) were disintegrated and deproteinized by homogenization in perchloric acid. After neutralization by potassium hydroxide the supernatant solution was used for determining thymosin beta 4 by reverse-phase HPLC without further manipulations. Not only does this procedure avoid artificial proteolysis as effectively as extraction of tissues by guanidinium chloride or boiling buffer, but it offers two further advantages. First, no additional steps--as for example desalting--are necessary prior to HPLC and thus the risk of losing thymosin beta 4 is eliminated. Using this procedure thymosin beta 4 is recovered quantitatively. The method is linear over the range 0.04 to 1.13 nmol and thymosin beta 4 is well separated from other thymosin beta 4-like peptides known to be present in mammals; i.e., thymosin beta Ala4, thymosin beta 9, thymosin beta 10, and thymosin beta Arg10. Second, the acid-insoluble pellet of the same extract can be used to determine the DNA content of the sample. Thus it is possible to relate thymosin beta 4 to DNA, which then allows comparing cells of different tissues and cell lines to one another. This procedure is also applicable to small peptides soluble in perchloric acid.

Amino Acid Sequence↗
PubMed1985

Biosynthesis rates and content of thymosin beta 4 in cell lines.

The content and relative biosynthetic rates of thymosin beta 4 have been determined in 28 different cell lines. The highest content of thymosin beta 4 as well as the highest rate of biosynthesis was observed in Epstein-Barr virus-transformed human B-cell lines. The levels observed in these cells are 1 pg thymosin beta 4 per cell, which is three times higher than that in rat peritoneal macrophages. Thus, these B-cell lines have the highest content of thymosin beta 4 of any cell type yet described. Since all of the Epstein-Barr virus-transformed B-cells described here grow in suspension, it is unlikely that the presence of thymosin beta 4 is related to anchorage in these cells. Thymosin beta 4 is not secreted by viable Epstein-Barr virus-transformed B cells in culture, suggesting some intracellular function of the peptide. These results indicate that these B-cell lines may be suitable for the study of thymosin beta 4 function.

Animals↗
PubMed1985

Amino acid pattern in human aqueous humor of patients with senile cataract and primary open-angle glaucoma.

21 amino acids have been determined in aqueous humor obtained during microsurgical intraocular procedures in 30 patients with senile cataract and 27 patients with primary open-angle glaucoma. All individual amino acids showed higher levels in the glaucomas than in the cataracts: this is valid at 2p less than 0.05 for threonine, serine, asparagine, glutamine, methionine, tyrosine, phenylalanine, histidine, tryptophan, and arginine.

Aged↗
PubMed1982

Synthesis of thymosin beta 4 by peritoneal macrophages and adherent spleen cells.

Thymosin beta 4, previously identified as a component of thymosin fraction 5 isolated from calf thymus, is synthesized by peritoneal macrophages derived from rats or mice, including cells from nu/nu mice. Identification of thymosin beta 4 containing [35S]methionine was based on its retention time in reverse-phase HPLC and the recovery of radioactivity in peptides generated by mild acid hydrolysis or by digestion with trypsin. Thymosin beta 4 is also synthesized by rat and mouse spleen cells, and evidence is presented for its release from these cells.

Animals↗
PubMed1982

Thymosins beta 8 and beta 9: two new peptides isolated from calf thymus homologous to thymosin beta 4.

Two new peptides, designated thymosin beta 8 and thymosin beta 9, respectively, have been isolated and their amino acid sequences established. Thymosin beta 8, isolated from calf thymus fraction 5, has a mass of 4518 daltons and contains 39 amino acid residues, of which 31 are identical to the corresponding amino acid residues in thymosin beta 4 isolated from the same source. The NH2 terminus of thymosin beta 8 is acetylalanine, compared with acetylserine in thymosin beta 4. Thymosin beta 9, isolated from fresh-frozen calf thymus by a procedure that minimizes proteolysis, is identical to thymosin beta 8 except for the presence of an additional dipeptide, -Ala-LysOH, at the COOH terminus. It has a mass of 4717 daltons and 32 of its 41 amino acids are identical to those of thymosin beta 4. The similarity in structures of thymosin beta 4 and thymosin beta 9 suggests that they may have related functions.

Animals↗
PubMed1982

Thymosin beta 4: a ubiquitous peptide in rat and mouse tissues.

Thymosin beta 4, recently isolated from calf thymus, is present in a number of rat and mouse tissues, including spleen, thymus, brain, lung, liver, and heart muscle. High concentrations are found in peritoneal macrophages, suggesting that its occurrence in other tissues may be related to the presence of macrophages or macrophage-like cells in these tissues. The conclusion that "thymosin" beta 4 does not originate solely in the thymus gland is supported by the high concentrations found in tissues of athymic (nu/nu) mice.

Animals↗
PubMed1981

Stimulation of growth by testosterone via the mesenchyme. Recombination of tissues from Tfm and wild-type preputial gland anlagen of mouse embryo.

To establish testosterone-dependent growth in organ-culture anlagen of preputial glands from normal wild-type and from androgen-insensitive mouse embryos carrying the testicular feminization mutation (Tfm) were explanted and cultured in the presence of testosterone. Within six days a size difference developed between Tfm and wild-type explants involving length of hair follicle, amount of preputial gland tissue, and overall size. Anlagen from Tfm and wild-type preputial glands were then separated into epithelial bud and mesenchyme. Reciprocal recombinants were prepared and cultured with testosterone. In the recombinants development of hair follicles and gland tissue was inconsistent. Nevertheless, the effect of testosterone was expressed in the overall size of the explants. The size correlated with the type of mesenchyme used, but not with the type of epithelium: Androgen-insensitive Tfm epithelium combined with wild-type mesenchyme reached the same size as whole wild-type glands and wild-type/wild-type recombinants. Wild-type epithelium with Tfm mesenchyme resulted in small explants, which were in the range of the whole androgen-insensitive Tfm glands. Tfm/Tfm recombinants showed very poor growth, probably related to the fact that in this group no hair or gland structures developed.

Androgen-Insensitivity Syndrome↗
PubMed1981

Purification of thymus mRNA coding for a 16,000-dalton polypeptide containing the thymosin alpha 1 sequence.

A mRNA fraction purified by preparative polyacrylamide disc gel electrophoresis from calf thymus polysomes codes for a polypeptide(s) having a mass of 16,000-17,000 daltons. This polypeptide contains amino acid sequences corresponding to residues 11-18 and 19-25 of thymosin alpha 1. The yield of the octapeptide indicates that the 16,000-dalton peptide is the major product formed in the cell-free synthesis system containing the purified mRNA.

Animals↗
PubMed1980

Demonstration of 2n spermatids in carriers of the "sex reversed" factor in the mouse by Feulgen cytophotometry.

The "Sex Reversed" factor (SXY) leads to development of XX males. The condition is transmitted by XY-Sxr males. The testes of XY-Sxr carriers are characterized by patches of defective spermatogenesis with meiotic failure and appearance of extraordinary large spermatids. In the present study DNA content of the large spermatids is determined by Feulgen DNA measurement using a scanning cytophotometer. The large spermatids in XY-Sxr testes are shown to be 2n.

Animals↗
PubMed1980

Effect of starvation and refeeding a high-protein or high-carbohydrate diet on lipid composition and glycogen content of rat livers in relation to age.

Rats of two different ages (72 and 490 days) were subjected to a 3-day fast and then refed for the same period a high-protein (89%) or high-carbohydrate (99%) diet. This experimental model served to study whether alterations occur in the content of the main lipid components, triacylglycerol, phospholipids and cholesterol in liver. It also examined whether the aging process itself has any effect on the lipid pattern. With the high-protein diet the content of all lipids returned to or nearly to the control level regardless of age. Refeeding the 72-day-old rats the high-carbohydrate diet led to a 2.4-fold overshoot in the triacylglycerol content, while the phospholipids and the cholesterol remained far below their control levels. In the 490-day-old rats the total lipids, phospholipids and cholesterol remained at the starvation level. With aging, the total cholesterol content showed a marked increase of about four-fold when corrected for growth.

Aging↗