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Biomedical subjects

E Lund

Publications and source records attributed to E Lund.

At least 343 records · Page 19Linked to original sources
PubMed1977

The use of omicron-phthalaldehyde for fluorescence detection in conventional amino acid analyzers. Sub-nanomole sensitivity in the analysis of phenylthiohydantoin-amino acids.

A conventional amino acid analyzer has been modified for fluorescence detection using omicron-phthalaldehyde. The original ninhydrin system is retained, and the amino acid analyzer can be used with either of the detection systems. The fluorescence detection is used for identification of PTH-amino acids after back hydrolysis, when nanomole amounts of proteins are sequenced. Impurities in the water and the chemicals used for buffer preparations are limiting factors for the sensitivity of the fluorescence detection system. A 100-fold increase in sensitivity above the original ninhydrin system is obtained.

Amino Acids↗
PubMed1977

Spacer transfer RNAs in ribosomal RNA transcripts of E. coli: processing of 30S ribosomal RNA in vitro.

At least three different transfer RNAs are produced by in vitro processing of 30S ribosomal RNA which accumulates in RNAase III- strains of E. coli. Two of these tRNAs, tRNAGlu2 and tRNAIle1, have previously been shown to be "spacer tRNAs"--that is, genes for their synthesis are located in rRNA transcription units between the cistrons for 16S and 23S rRNAs (Lund et al., 1976). The third tRNA whose sequences are contained in 30S rRNA is tRNAAla1B. In addition to the tRNAs, 5S rRNA and several other 4S fragments are produced. Some of these 4S fragments may represent additional spacer tRNAs. One fragment, about 70 nucleotides long, arises from the 5' end of the 17S precursor of 16S rRNA. Four or five other tRNAs are hydrogen-bonded to 30S rRNA as we prepare it; one or more of these tRNAs may also be a spacer tRNA. The enzymes that process tRNAs out of 30S rRNA are associated with ribosomes, but can be removed from them by washing in 0.2 M NH4Cl; the enzymes required for 5S rRNA processing remain bound to the 0.2 M NH4Cl-washed ribosomes. Treatment of 30S rRNA with purified RNAase III produces 6-8S fragments which contain the sequences of tRNAGlu2, tRNAAla1B and 5S rRNA.

Base Sequence↗
PubMed1977

Low concentration of plasma amino acids in newborn babies of diabetic mothers.

Plasma amino acid concentrations were measured in maternal peripheral vein and in umbilical vein and artery at birth (caesarean section) in 6 diabetic and 5 non-diabetic pregnancies. The mean birth weight in the control group amounted to 3.9 kg as oversize of the foetus in three cases contributed to the indication for caesarean section. The infants in the diabetic group consisted of "small for gestational age" babies (mean weight 2.8 kg). Free amino acid levels in the normal group and in diabetic maternal blood were in agreement with previous investigations. No difference in amino acid concentrations in the maternal plasma was found, but the concentrations of the umbilical vein plasma were significantly lower in the diabetic group. Foetal hyperinsulinaemia may be a cause of the low amino acid concentrations. Besides, abnormalities of the placenta and maternal vascular complications increase and the mean birth weights decrease significantly through the White classes. Conditions of impairment of placental transfer of amino aicds may thus be present. Characteristics features of the foetus may be consistent with the hypothesis as follows: The foetus in diabetic pregnancy is in varying degree exposed to an oversupply of glucose, hyperinsulinaemia, imbalanced uptake and a slightly diminished supply of amino acids.

Amino Acids↗
PubMed1976

Transfer RNA genes between 16S and 23S rRNA genes in rRNA transcription units of E. coli.

We have identified genes for tRNAGLU/2 on the transducing phages o80d3ilvsu7+ (see Ohtsubo et al., 1974) and lambdarifd18 (Kirschbaum and Konrad, 1973), and a gene for tRNAlle/1 on the transducing phage o80rifr (Konrad, Kirschbaum, and Austin, 1973). All these phages have previously been shown to carry genes for rRNA (Ohtsubo et al., 1974; Lindahl et al., 1975; Jaskunas et al., 1975a). We have analyzed the position of these tRNA genes by hybridizing purified RNAs to restriction fragments of the phage DNA. The tRNA genes are located inside the rRNA transcription unit in the spacer region between the 16S and 23S rRNA genes.

Chromosome Mapping↗
PubMed1976

Prophylactic, postinfectious and neonatal vaccination against canine distemper in mink.

Mink were vaccinated against canine distemper and challenged with the Snyder Hill strain of canine distemper virus. Protection was acquired if vaccination took place more than a few days before challenge. If vaccination took place even early during incubation mortality was higher than in the unvaccinated controls. Full protection of kits may be achieved even at an age of 16 to 20 days provided the kits had not passively acquired immunity from their mothers. Kits surviving distemper because of passively acquired immunity may not actively acquire immunity during infection and may die at a later exposure.

Animals↗
PubMed1976

Serological types of Diplococcus pneumoniae isolated from the respiratory tract of children with cystic fibrosis and children with other diseases.

The distribution of serological types of D. pneumoniae was investigated in 40 strains isolated from 26 children with cystic fibrosis and 57 strains isolated from 39 children with other diseases. All strains were isolated from sputum or tracheal secretion. The strains from cystic fibrosis patients belonged to 14 different serological types, the most prevalent were 19F, 19A and 3. The strains from the other group of children belonged to 20 different serological types, the most prevalent were 23F, 19F and 11A. The differences between the two groups of patients as to the prevalences of types were small, and it is concluded that no special serological types of D. pneumoniae are associated with cystic fibrosis.

Adolescent↗
PubMed1975

Hybridization of labeled RNA to DNA in agarose gels.

Specific DNA restriction endonuclease fragments can be identified after electrophoresis in agarose gels by hybridization in the gel (in situ) to radioactive homologous RNA. RNA-DNA hybrids are detected by autoradiography of the gel. Comparison of band patterns of the autoradiogram and the ethidium bromide stained gel allows the identification of the DNA fragment which is complementary to the RNA probe. The technique is rapid, easy and inexpensive. It is sensitive enough to detect individual genes in a mixture of fragments produced by restriction enzyme digestion of complex cellular DNA. We have used this technique to determine which of the Hin III and Eco R1 fragments of phi80d3ilv+su+7 and E. coli DNAs contain the 5S, 16S and 23S ribosomal RNA (rRNA) genes of E. coli.

DNA↗
PubMed1975

The possible utilization of nuclear pockets of lymphocytes in the diagnosis of enzootic bovine leucosis.

A comparative study of the presence of lymphocytosis and nuclear pockets in lymphocytes was carried out using blood samples from animals belonging to herds with bovine enzootic leucosis and from herds free from leucosis. It was found that there was a correlation between the presence of such nuclear projections in a certain percentage of the lymphocytes and a state of lymphocytosis. As this correlation seemed to be independent of the aetiology of the lymphocytosis, it was not considered possible to employ the demonstration of nuclear pockets as a more specific tool in the diagnosis of bovine enzootic leucosis than the lymphocyte counts in themselves.

Animals↗
PubMed1975

Inactivation of enterovirus by glutaraldehyde.

A study on the rate of inactivation by glutaraldehyde of coxsackievirus was conducted using different concentrations, temperatures, and pH values. It was found, that 2 percent glutaraldehyde at pH 7.4 and 25 C, as recommended for a sporicide, reduced the titer of infectious virus by 2 log10U in 1 min or less. The reduction was not negatively affected by high concentrations of organic matter (serum and animal spillings) in the reaction mixtures.

Aldehydes↗