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Biomedical subjects

A Brandt

Publications and source records attributed to A Brandt.

At least 145 records · Page 8Linked to original sources
PubMed1990

A plant serpin gene. Structure, organization and expression of the gene encoding barley protein Z4.

A 3133-bp nucleotide sequence of the gene Paz1 on chromosome 4 of barley, encoding endosperm protein Z4, has been determined. The sequence includes 1079 bp 5' upstream and 523 bp 3' downstream of the coding region. The 1079-bp 5' upstream region of the gene shows little similarity to 5' regions of other sequences genes expressed in the developing cereal endosperm. The coding sequence is interrupted by one 334-bp-long intron (bases 1497-1830). The deduced amino acid sequence, which was corroborated by peptide sequences, consists of 399 amino acids and has a molecular mass of 43,128 Da. This sequence confirms protein Z4 to be a member of the serpin superfamily of proteins. The similarity with other members of the family expressed as amino acids in identical positions is in the order of 25-30% and pronounced in the carboxy-terminal half of the molecule. Sequence residues assumed to form clusters stabilizing the tertiary structure are highly conserved. Protein Z4 is synthesized in the developing endosperm without a signal peptide and protein Z4 mRNA was evenly distributed among the free and membrane-bound polyribosomes of the endosperm cell. An internal hydrophobic region of 21 amino acids (residues 36-56) may serve as a signal for targeting the polypeptide into the lumen of the endoplasmic reticulum. The gene for protein Z4 could not be detected in the barley variety Maskin and some of its descendants. The 'high-lysine' allees, lys1 (Hiproly barley) and lys3a (Bomi mutant 1508) on chromosome 7, enhance and repress, respectively, the expression of the protein Z4 gene. Also, 1554 bp of another 8-kbp fragment of the barley genome Paz psi, similar to the protein-Z4-coding region, have been determined. Small insertions and deletions and the presence of an internal stop codon identify this fragment as part of a pseudogene related to the protein Z4 gene.

Amino Acid Sequence↗
PubMed1990

Protein import into yeast mitochondria is accelerated by the outer membrane protein MAS70.

The yeast mitochondrial outer membrane contains a major 70 kd protein with an amino-terminal hydrophobic membrane anchor and a hydrophilic 60 kd domain exposed to the cytosol. We now show that this protein (which we term MAS70) accelerates the mitochondrial import of many (but not all) precursor proteins. Anti-MAS70 IgGs or removal of MAS70 from the mitochondria by either mild trypsin treatment or by disrupting the nuclear MAS70 gene inhibits import of the F1-ATPase beta-subunit, the ADP/ATP translocator, and of several other precursors into isolated mitochondria by up to 75%, but has little effect on the import of porin. Intact cells of a mas70 null mutant import the F1-ATPase alpha-subunit and beta-subunits, cytochrome c1 and other precursors at least several fold more slowly than wild-type cells. Removal of MAS70 from wild-type mitochondria inhibits binding of the ADP/ATP translocator to the mitochondrial surface, indicating that MAS70 mediates one of the earliest import steps. Several precursors are thus imported by a pathway in which MAS70 functions as a receptor-like component. MAS70 is not essential for import of these precursors, but only accelerates this process.

Cytochromes c1↗
PubMed1990

[Variation of bone density in relation to age: analysis of 259 necropsies].

In a previous study we reported a relatively low incidence of hip fracture in our population compared to figures reported elsewhere and speculated that this could be related to differences in bone density. Accordingly, we measured bone density in 259 subjects at necropsy. In 172 males we found that bone density decreased from 0.88 g/cc at age 21-30 to 0.80 at age 70 (NS). In women, density decreased from 1.0 at age 21-30 to 0.84 at age 50, 0.69 at age 60 and 0.64 in those older than 70 years (p less than 0.01). These figures are higher than those reported from USA at all ages and could explain the lower incidence of hip fractures in our population.

Adult↗
PubMed1990

[Postmenopausal women: changes in plasma lipids with different estrogen replacement therapies].

We measured total, HDL and LDL cholesterol and triglycerides in 183 postmenopausal women before and 4 weeks after hormone therapy. Ethinyl estradiol or conjugated estrogens alone or in association with medroxyprogesterone, norethyndrone or norgestrel were used in different dosages either continuously or sequentially. Total cholesterol decreased from 206 to 196 mg/dl and HDL raised from 47 to 53 mg/dl (p less than 0.001) except in the group treated with estradiol-levonorgestrel in which HDL fell from 41 to 36 mg/dl (p less than 0.001). HDL cholesterol decreased from 133 to 113 mg/dl, overall. The total cholesterol/HDL ratio decreased from 4.8 to 4.2 in all groups except the group previously mentioned. Estrogen therapy, isolated or in association to medroxyprogesterone induced a moderate increase in serum triglyceride levels (132 to 149 mg/dl, p less than 0.001). Thus, the administration of estrogens in postmenopausal women is associated with a decrease in total, LDL and total/HDL cholesterol ratio and an increase in triglycerides. Norgestrel but not medroxyprogesterone partially revert these effects.

Adult↗
PubMed1989

New potential immunoenhancing compounds. Synthesis and pharmacological evaluation of new long-chain 2-amido-2-deoxy-D-glucose derivatives.

A series of long-chain fatty acids and the corresponding 2-hydroxy, 2-oxo, 3-hydroxy acid glucosamides were evaluated as immunomodulating compounds. In a preliminary screening, 2-[(2-ethoxycarbonyloxy)tetradecanoylamino]-2-deoxy-D-glucos e (2b) and 2-(3-hydroxydodecanoylamino)-2-deoxy-D-glucose (5a) resulted to be the most effective in enhancing the glucosamine activity. The findings of in vitro-ex vivo tests (unidirectional mixed lymphocyte culture reaction and primary antibody production) and in vivo tests (delayed type hypersensitivity, protection against bacterial or fungal infection and against Sarcoma 180 or Lewis lung carcinoma transplants) were very encouraging and allowed to assume for the two substances a protective activity, presumably through the ability of activating phagocytic and NK cells.

Adjuvants, Immunologic↗
PubMed1988

Synthesis and in vitro antibacterial activity of a new series of monobactam derivatives.

Using as a model monobactams with a substituted alpha-oxyimino moiety in the side chain (aztreonam), a series of 2-(2-aminothiazol-4-yl)-2-hydrazono-acetamido monobactam (II a, f) were prepared by condensation of the hydrazones (I a, e) (Z form) with tetrabutylammonium 3-amino-4-methyl-2-oxo-1-azetidin-sulphonate. Isomerization occurred during this synthesis and gave the E form of all compounds. Monobactams (II a, f) showed no significant in vitro antibacterial activity when compared with aztreonam and with some cephalosporins bearing the same E-hydrazono side chain.

Anti-Bacterial Agents↗
PubMed1987

Synthesis and pharmacological evaluation of a new class of 2-(2-aminothiazol-4-yl)-2-hydrazonoacetamido cephalosporins.

A series of 2-(2-aminothiazol-4-yl)-2-hydrazonoacetamido cephalosporins 1a-h was prepared. Whenever possible, E and Z isomers were isolated, and their relative stabilities and their interconversions were tested. The antibacterial activity was tested against Gram-positive and Gram-negative bacteria. For compound 1c, whose Z and E forms do not interconvert rapidly, the Z form was the more active one. Among the other compounds, for which the E form is the only stable one for practical purposes, compound 1a was the most active. When compared with cefuroxime and cefotaxime, compound 1a showed slightly lower antibacterial activity but good serum level and half-life values.

Acetamides↗
PubMed1986

Primary structure of the (1-->3,1-->4)-beta-D-glucan 4-glucohydrolase from barley aleurone.

During germination of barley grains, the cell walls of the starchy endosperm are degraded by (1-->3,1-->4)-beta-glucanases (EC 3.2.1.73) secreted from the aleurone and scutellar tissues. The complete sequence of the aleurone (1-->3,1-->4)-beta-glucanase isoenzyme II comprises 306 amino acids and was determined by sequencing nine tryptic peptides (110 residues) and aligning them with the amino acid sequence deduced from a cDNA clone encoding the 291 NH(2)-terminal residues. Although no amino acid sequence homology with a bacterial (1-->3)(1-->4)-beta-glucanase is apparent, close to 50% homology is found with two large regions of a (1-->3)-beta-glucanase from tobacco pith tissue. The gene for barley (1-->3,1-->4)-beta-glucanase isoenzyme II shares with that for the alpha-amylase isoenzyme 1 a strongly preferred use of codons with G and C in the wobble position (94% and 90%, respectively). Both enzymes are secreted from the aleurone cells during germination. Such one-sided codon usage is not characteristic for the gene encoding the (1-->3)-beta-glucanase of tobacco pith tissue or the hor2-4 gene encoding the B(1) hordein storage protein in the endosperm.

Journal Article↗
PubMed1986

[Clonogenic growth of tumor cells in vitro].

We expose here our first results concerning clonogenic growth of 40 cases of malignant tumor plated in semi-solid medium (methylcellulose). The growth is determined by the presence at day 21 of colonies (cellular group with more than 60 micron diameter). 26 cases were considered significant. A 61% growth has been observed with primary solid tumors, and 83.4% with ascites, ovarian carcinoma growing the best. Cellular viability, plating efficiency and when the cellular number allowed it, linear graphic curves have been established. An ultrastructural morphological study, illustrated here by 2 cases--one ovarian carcinoma and one colonic adenocarcinoma cell line--has shown that all colony 's cells belong to a same cellular type and present various degrees of differentiation, suggesting a possible analogy between our observations and the hypothetical tumor cell model, concerning human carcinoma's organisation and self renewal.

Cell Division↗
PubMed1985

Messenger RNAs from the Scutellum and Aleurone of Germinating Barley Encode (1-->3,1-->4)-beta-d-Glucanase, alpha-Amylase and Carboxypeptidase.

Polyclonal antibodies raised against barley (1-->3,1-->4)-beta-d-glucanase, alpha-amylase and carboxypeptidase were used to detect precursor polypeptides of these hydrolytic enzymes among the in vitro translation products of mRNA isolated from the scutellum and aleurone of germinating barley. In the scutellum, mRNA encoding carboxypeptidase appeared to be relatively more abundant than that encoding alpha-amylase or (1-->3,1-->4)-beta-d-glucanase, while in the aleurone alpha-amylase and (1-->3,1-->4)-beta-d-glucanase mRNAs predominated. The apparent molecular weights of the precursors for (1-->3,1-->4)-beta-d-glucanase, alpha-amylase, and carboxypeptidase were 33,000, 44,000, and 35,000, respectively. In each case these are slightly higher (1,500-5,000) than molecular weights of the mature enzymes. Molecular weights of precursors immunoprecipitated from aleurone and scutellum mRNA translation products were identical for each enzyme.

Journal Article↗
PubMed1984

Complete amino acid sequence of the N-terminal extension of calf skin type III procollagen.

The N-terminal extension peptide of type III procollagen, isolated from foetal-calf skin, contains 130 amino acid residues. To determine its amino acid sequence, the peptide was reduced and carboxymethylated or aminoethylated and fragmented with trypsin, Staphylococcus aureus V8 proteinase and bacterial collagenase. Pyroglutamate aminopeptidase was used to deblock the N-terminal collagenase fragment to enable amino acid sequencing. The type III collagen extension peptide is homologous to that of the alpha 1 chain of type I procollagen with respect to a three-domain structure. The N-terminal 79 amino acids, which contain ten of the 12 cysteine residues, form a compact globular domain. The next 39 amino acids are in a collagenase triplet sequence (Gly- Xaa - Yaa )n with a high hydroxyproline content. Finally, another short non-collagenous domain of 12 amino acids ends at the cleavage site for procollagen aminopeptidase, which cleaves a proline-glutamine bond. In contrast with type I procollagen, the type III procollagen extension peptides contain interchain disulphide bridges located at the C-terminus of the triple-helical domain.

Amino Acid Sequence↗