Chemical characterization of thymosin beta 4.

As part of our ongoing investigations on the endocrine thymus, we have isolated and purified to homogeneity a hormone-like peptide which we have termed thymosin beta 4. Thymosin beta 4 has Mr = 4982 and an isoelectric point of 5.1.

The surface finish of the new microfill restorative materials. A scanning electron microscope study.

Surface smoothness is an important requirement for restorative materials. Recently, restorative materials claimed to be inherently smooth in surface characteristics have been developed. Matrix-formed and finished surfaces of five new microfill restorative materials were compared with two composite resins, an acrylic resin and a silicate cement by means of scanning electron microscopy.

The combined application of topical fluoride and fissure sealant--results after 2 years.

The effectiveness of combining the application of topical stannous fluoride and fissure sealing using Nuva Seal was tested in a group of school children over a 2-year period. The retention rate of the applied sealant was 71.1%.

Modulation of terminal deoxynucleotidyl transferase activity by thymosin.

Thymosin fraction 5, a family of acidic polypeptides isolated from bovine thymus, contains several hormonal-like factors which have been shown to influence the maturation, differentiation and functions of T-cells. Some of these peptides have been chemically defined. Two of them, thymosin alpha 1 (M.

Thymosin stimulates secretion of luteinizing hormone-releasing factor.

Partially purified thymosin fraction 5 and one of its synthetic peptide components, thymosin beta 4, but not thymosin alpha 1, stimulated secretion of luteinizing hormone--releasing factor from superfused medial basal hypothalami from random cycling female rats. In addition, luteinizing hormone was released from pituitary glands superfused in sequence with hypothalami. No release of luteinizing hormone in response to thymosin was observed from pituitaries superfused alone.

Complete amino acid sequence of bovine thymosin beta 4: a thymic hormone that induces terminal deoxynucleotidyl transferase activity in thymocyte populations.

The amino acid sequence of thymosin beta 4, a polypeptide isolated from calf thymus, was determined. Thymosin beta 4 is composed of 43 amino acid residues and has a molecular weight of 4982 and an isoelectric point of 5.1.

The treatment of hypersensitive cervical abrasion cavities using ASPA cement.

This study evaluated the usefulness of the alumino-silicate polyacrylate (ASPA) or glass ionomer cement in the treatment of hypersensitive cervical abrasion cavities. Various methods of treatment of hypersensitive cervical abrasion cavities have been described, and all these methods have their disadvantages. The ASPA cement was used to treat non-carious hypersensitive cervical abrasion cavities in 189 teeth from fifty-eight adult patients.

Production of biologically active N alpha-desacetylthymosin alpha 1 in Escherichia coli through expression of a chemically synthesized gene.

Thymosin alpha 1, an immune restorative polypeptide hormone, was synthesized in Escherichia coli by using recombinant DNA cloning techniques. Based on the known amino acid sequence, a gene coding for the thymosin alpha 1 polypeptide chain was designed and enzymatically assembled from chemically synthesized oligodeoxyribonucleotide fragments. The gene was ligated into plasmid pBR322 and placed under lac operon control, and N alpha-desacetylthymosin alpha 1 was expressed as part of a beta-galactosidase chimeric protein.

Thymosin: basic properties and clinical application in the treatment of immunodeficiency diseases and cancer.

Thymosin fraction 5 contains a family of polypeptides with varying biological activities. Current efforts in the thymosin research program are involved in further chemical characterization of thymosin peptides and evaluation of clinical immunotherapeutic protocols. Recent clinical studies with thymosin fraction 5 have shown therapeutic potentials for treatment of patients with primary immunodeficiency diseases and cancer.

Primary structure of a human IgA1 immunoglobulin. III. Isolation, composition, and amino acid sequence of the thermolysin peptides.

As part of the strategy for determination of the complete covalent structure of a human IgA immunoglobulin, 66 peptides were isolated from a thermolysin digest of reduced and carboxymethylated IgA alpha1 chain Bur and were purified. They range in length from 2 to 24 residues. Some of the peptides have been characterized and sequenced in order to supply needed information that was not obtained from the chymotryptic and tryptic peptides.

Primary structure of a human IgA1 immunoglobulin. II. Isolation, composition, and amino acid sequence of the tryptic peptides of the whole alpha1 chain and its cyanogen bromide fragments.

As part of the strategy for determining the covalent structure of a human IgA1 molecule (Bur), a tryptic digest was prepared of the reduced and carboxymethylated alpha1 heavy chain. In addition to the main experiment, tryptic peptides were prepared from the succinylated aminoethylated alpha1 chain and from fragments obtained by CNBr scission of the alpha1 chain. Complete recovery of the peptides was impeded by the large size of some of the tryptic peptides and of the principal CNBr fragment, and difficulty in separating other glycopeptides.

Primary structure of a human IgA1 immunoglobulin. IV. Streptococcal IgA1 protease, digestion, Fab and Fc fragments, and the complete amino acid sequence of the alpha 1 heavy chain.

In order to establish the complete amino acid sequence of the human IgA alpha1 chain Bur, IgA1 protease from Streptococcus sanguis was employed to generate Fabalpha and Fcalpha fragments in the final stage of this investigation. Cyanogen bromide cleavage of the Fabalpha fragment followed by reduction and aminoethylation produced the Fd' fragment (residues 84 to 227); this contains part of the variable region (VR), the whole first constant domain (Calpha1), and part of the hinge region of this heavy chain. The tryptic peptides of the Fd' fragment were isolated, characterized, and sequenced.

The chemistry and biology of thymosin. II. Amino acid sequence analysis of thymosin alpha1 and polypeptide beta1.

The amino acid sequences of two polypeptide components of thymosin Fraction 5 termed thymosin alpha1 and polypeptide beta1 have been established. The sequences were determined by automatic Edman degradation of the intact molecules as well as by manual sequence analysis of the enzymatic cleavage products. Thymosin alpha1, an immunologically active polypeptide, is highly acidic with an isoelectric point of 4.

The chemistry and biology of thymosin. I. Isolation, characterization, and biological activities of thymosin alpha1 and polypeptide beta1 from calf thymus.

A partially purified extract from thymus tissue termed thymosin Fraction 5 has been shown to reconstitute immunological deficiencies resulting from the lack of thymic function in several animal models, as well as humans with primary and secondary immunodeficiency diseases. Thymosin Fraction 5 consists of a family of polypeptides with molecular weights ranging from 1,000 to 15,000. Several of these polypeptides contribute individually to the biological activity of the parent compound.

Current status of thymosin research: evidence for the existence of a family of thymic factors that control T-cell maturation.

Thymosin fraction 5 contains several distinct hormonal-like factors which are effective in partially or fully inducing and maintaining immune function. Several of the peptide components of fraction 5 have been purified, sequenced and studied in assay systems designed to measure T-cell differentiation and function. These studied indicate that a number of the purified peptides act on different subpopulations of T-cells (see Figure 1).

Overview of thymosin activity.

Our current research program centers around the biologic and chemical characterization of the family of polypeptides present in thymosin fraction 5. A system of nomenclature has been developed and the peptides are being systematically isolated and chemically characterized. Thymosin fraction 5 and its component parts influence a variety of lymphocyte properties including cyclic nucleotide levels, migration inhibitory factor production, T-dependent antibody production, and expression of certain surface markers.

The adaptation of composite materials to etched enamel surfaces.

The adaptation of three composite materials and one unfilled bis-GMA resin to etched enamel surfaces was investigated by examining under optical and scanning electron microscopy the adhesive-enamel junction of replicas. The length of the tags and the density of tagging observed on the replicas showed that the three composite materials, Adaptic, Concise and Delphic, adapted to the etched enamel surface equally as well as the unfilled resin Nuva Seal. The results of this study together with available results of mechanical testing and clinical studies allow the conclusion that the successful retention of the composite filling materials to an etched enamel surface is not dependent on the use of an intermediate unfilled resin or bonding agent.