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Biomedical subjects

M Baer

Publications and source records attributed to M Baer.

At least 55 records · Page 3Linked to original sources
PubMed1992

Structure/histotoxicity relationship of parenteral iron preparations.

Commercial iron preparations with different chemical structures and stabilities which are indicated for parenteral application were analyzed. After intravenous application in mice, toxic effects were screened by histological examination of liver, kidney, adrenal, lung and spleen. The various iron complexes were classified into four groups according to their physicochemical properties (molecular mass, kinetic and thermodynamic stability). It was found that the toxic effects can be forecasted by the chemical properties. The results clearly show that not all iron preparations tested can be recommended for intravenous application. After injection, the ideal iron preparation is deposited in the reticulo-endothelial system, and not in the parenchyma of the liver, nor mainly in the periportal area. Furthermore, its renal elimination rate should be below 1% of the dose, and there should be practically no iron detectable in the tubuli. The molecular mass of an optimal product is between 30,000 and 100,000 Daltons, and the preparation does not contain any slowly degradable biopolymers, so that the incidence of allergic side effects is reduced to a minimum. Iron preparations consisting only of weak iron complexes, which liberate iron ions stochastically, should not be used for intravenous application.

Animals↗
PubMed1991

Evaluation of live attenuated varicella vaccine (Oka-RIT strain) and combined varicella and MMR vaccination in 13-17-month-old children.

The Oka-RIT strain of live attenuated varicella vaccine at dose levels 5300 PFU (high titre) and 2000 PFU (low titre) was tested in 13-17-month-old children; 50% of the children received the varicella vaccine alone, and the other 50% received it together with a measles-mumps-rubella (MMR) vaccine. The high titre and low titre varicella vaccines induced 96% and 92% seroconversion rates, respectively. Following combined vaccination with MMR, the corresponding seroconversion rates for varicella were significantly lower at 85% and 72% respectively. Seroconversion rates to measles, mumps and rubella were not affected by the combination of varicella vaccine plus MMR vaccination. Single varicella vaccine at both titre levels was found safe, although 10% of the children had minor skin reactions, possibly attributable to the vaccine. Reactions typically associated with MMR vaccination did not significantly increase after the combined varicella plus MMR vaccination. This study confirmed that the Oka-RIT strain varicella vaccine is safe and immunogenic in healthy young children, but failed to find a totally satisfactory combination for a varicella-MMR vaccine.

Antibodies, Viral↗
PubMed1991

Investigation on the dosage/efficacy relationship of iron dextran in veal calves.

The efficacy of a single dose of 800 mg resp. 1600 mg iron in the form of an intramuscularly administrable iron (III)-dextran complex (Anaemex, CAS 9004-66-4) has been tested. On 3 groups of 13 calves each, 0 ml (comparing group), 4 ml resp. 8 ml iron dextran 20% have been applied. All calves received iron-containing food during the test period of 10 weeks. At the beginning of the therapy, 5 weeks and 8 weeks after application, the parameters: weight, hemoglobin, erythrocytes, hematocrit, mean corpuscular hemoglobin (MCH), MCH concentration, mean corpuscular volume, plasma protein, fibrinogen, leukocytes and serum iron were measured. After 10 weeks the dead weight has been determined and the spleen of some calves tested histologically. The study shows that, by the administration of 1600 mg iron as a depot injection, a better growth results with the same quality of veal. The red-coloring of the veal was not significantly different from that of the comparing group. The histological findings show especially that the iron depots of the spleen were empty in all three groups and thereby in this collective no connection exists between the color of the veal and the tested dosage of iron dextran 20%. It is considered meaningful and economic to renounce in future the iron-containing food and in its place to apply intramuscular a single dose of 1600-2400 mg iron per calf. The results are compared with a study on full term infants, which has shown that a intramuscular single dose of 150 mg of iron as iron dextran at birth affords a nutritional advantage in iron status for up to 15 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Structure and transcription of a human gene for H1 RNA, the RNA component of human RNase P.

The gene coding for H1 RNA, the RNA component of human RNase P, has been isolated and characterized from a human genomic DNA library. The sequence corresponding to the mature H1 RNA is almost identical to that previously identified using H1 RNA and a cDNA clone corresponding to it. The nucleotide sequence of the genomic clone contains an array of potential transcriptional control elements, some characteristic of transcription by RNA polymerase III and some characteristic of RNA polymerase II, as is also the case for U6 and certain other small stable RNAs. The transcription in vitro of the genomic clone shows that the gene is functional and is transcribed by RNA polymerase III. Southern hybridization analysis indicates that there is very likely only one copy of the gene for H1 RNA in the human genome.

Base Sequence↗
PubMed1990

A new enzyme immunoassay for prolactin in serum or plasma.

This enzyme immunoassay (EIA) of human prolactin (hPRL) involves incubation of sample and anti-hPRL antibodies conjugated to horseradish peroxidase (EC 1.11.1.7) in tubes coated with a second antibody to hPRL. The test can be performed within 60 min. No reaction of the antibodies with human placental lactogen and human somatotropin is detectable. The presence of detergent allows assay of both serum and plasma. Precision was improved by including polyethylene glycol in the reaction mixture. To optimize analytical recovery, we added protease inhibitor. Assay of the EIA standards shows good correlation with results for World Health Organization reference preparations. The measurable range is 1 to 400 micrograms/L. Intra- and interassay CVs are about 5%. Comparisons with two RIAs and two other EIAs show reasonably good correlations. The components of our EIA are stable for 18 months.

Antibodies, Monoclonal↗
PubMed1989

An immunological determinant of RNase P protein is conserved between Escherichia coli and humans.

RNase P, an enzyme with RNA and protein subunits, cleaves tRNA precursor molecules to form the 5' termini of mature tRNAs in both prokaryotes and eukaryotes. Rabbit antibodies made against the protein subunit, C5 protein, of Escherichia coli RNase P bound RNase P protein from E. coli and Bacillus subtilis in immunoblots and solid-phase immunoassays. These rabbit anti-C5 antibodies also bound a protein (Mr approximately 40,000) in preparations of RNase P from human (HeLa) cells and depleted the enzymatic activity from preparations of RNase P from both human and E. coli cells. Finally, rabbit anti-C5 antibodies immunoprecipitated from crude extracts of human cells a ribonucleoprotein complex containing H1 RNA, the putative RNA component of human RNase P. These results show that an antigenic determinant is shared by C5 protein from E. coli RNase P and a protein component of RNase P from human cells.

Antibodies↗
PubMed1989

M protein (M1) of influenza virus: antigenic analysis and intracellular localization with monoclonal antibodies.

A panel of 16 monoclonal antibodies recognizing M protein (M1) of influenza virus was generated. Competition analyses resulted in localization of 14 monoclonal antibodies to three antigenic sites. Three monoclonal antibodies localized to site 1B recognized a peptide synthesized to M1 (residues 220 to 236) with enzyme-linked immunosorbent assay titers equivalent to or greater than that seen with purified M1; therefore, site 1B is located near the C terminus of M1. Sites 2 and 3 localize to the N-terminal half of M1. Antigenic variation of M proteins was seen when the monoclonal antibodies were tested against 14 strains of type A influenza viruses. Several monoclonal antibodies showed specific recognition of A/PR/8/34 and A/USSR/90/77 M proteins and little or no reactivity for all other strains tested. Immunofluorescence analysis with the monoclonal antibodies showed migration of M protein to the nucleus during the replicative cycle and demonstrated association of M protein with actin filaments in the cytoplasm. Use of a vaccinia virus recombinant containing the M-protein gene demonstrated migration of M protein to the nucleus in the absence of synthesis of gene products from other influenza virus RNA segments.

Amino Acid Sequence↗
PubMed1989

Photolyases from Saccharomyces cerevisiae and Escherichia coli recognize common binding determinants in DNA containing pyrimidine dimers.

DNA photolyases catalyze the light-dependent repair of pyrimidine dimers in DNA. The results of nucleotide sequence analysis and spectroscopic studies demonstrated that photolyases from Saccharomyces cerevisiae and Escherichia coli share 37% amino acid sequence homology and contain identical chromophores. Do the similarities between these two enzymes extend to their interactions with DNA containing pyrimidine dimers, or does the organization of DNA into nucleosomes in S. cerevisiae necessitate alternative or additional recognition determinants? To answer this question, we used chemical and enzymatic techniques to identify the contacts made on DNA by S. cerevisiae photolyase when it is bound to a pyrimidine dimer and compared these contacts with those made by E. coli photolyase and by a truncated derivative of the yeast enzyme when bound to the same substrate. We found evidence for a common set of interactions between the photolyases and specific phosphates in the backbones of both strands as well as for interactions with bases in both the major and minor grooves of dimer-containing DNA. Superimposed on this common pattern were significant differences in the contributions of specific contacts to the overall binding energy, in the interactions of the enzymes with groups on the complementary strand, and in the extent to which other DNA-binding proteins were excluded from the region around the dimer. These results provide strong evidence both for a conserved dimer-binding motif and for the evolution of new interactions that permit photolyases to also act as accessory proteins in nucleotide excision repair. The locations of the specific contacts made by the yeast enzyme indicate that the mechanism of nucleotide excision repair in this organism involves incision(s) at a distance from the pyrimidine dimer.

Base Sequence↗
PubMed1987

A comparative trial of rapid oral and intravenous rehydration in acute diarrhoea.

37 children under the age of 5 years hospitalized for acute diarrhoea and dehydration were randomized to receive oral or intravenous rehydration during 6 to 12 hours. Rehydration was satisfactory in both groups, with correction of dehydration, metabolic acidosis and sodium deficit at equal rates. The reintroduction of normal feedings was successful in most of the orally rehydrated children after 12 hours, but often unsuccessful in the i.v. therapy group. Consequently the orally rehydrated children showed a 2.9% weight gain by the time of discharge whereas the intravenously treated children did not gain weight in the hospital. The duration of diarrhoea was also shorter in the orally rehydrated children. Thus oral rehydration therapy was equal or superior to even rapid intravenous rehydration therapy in the management of acute diarrhoea in children.

Acute Disease↗