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Biomedical subjects

J Carlson

Publications and source records attributed to J Carlson.

At least 253 records · Page 14Linked to original sources
PubMed1985

Identification of the stable free radical tyrosine residue in ribonucleotide reductase. A sequence comparison.

The small subunit of ribonucleoside diphosphate reductase contains a unique tyrosine radical and a binuclear iron center. An alignment of different primary structures of the small subunit in Escherichia coli, the marine mollusc Spisula solidissima, Epstein Barr and Herpes simplex viruses shows that regions comprising residues 115-122, 204-212 and 234-241 (in E.coli numbering) are strikingly similar and are likely to be recognized as functionally important. Two of 16 tyrosine residues and 2 of 8 histidine residues are conserved. We propose that Tyr-122 is responsible for radical stabilization and that His-118 and His-241 together with Glu-115 and Asp-237 or Glu-238 are ligands of the iron center.

Animals↗
PubMed1985

The structural proteins of the autonomous parvovirus feline panleukopenia virus.

Approximately 80% of the genome of feline panleukopenia virus was cloned into the plasmid pBR322. The entire 3943 nucleotide sequence of the cloned portion of FPV was determined. This DNA includes the gene which codes for the structural proteins of the virus. Portions of this gene were expressed in E. coli as fusion proteins with bacterial proteins. Some of the fusion proteins were capable of raising neutralizing antibodies in guinea pigs. Through the use of deletion mapping, monoclonal antibodies, and synthetic peptides, attempts were made to localize the portion of the protein responsible for raising these antibodies.

Animals↗
PubMed1985

Nuclear ploidy of neonatal rat livers: effects of two hepatic carcinogens (mirex and dimethylnitrosamine).

The effect of two hepatic carcinogens, dimethylnitrosamine (DMN) (genotoxic) and mirex (epigenetic), on polyploidization in 12-d-old neonatal rats was investigated by Coulter counteranalysis and [3H] thymodine uptake in isolated hepatic nuclear classes. DMN disturbed the normal ploidy development in the neonatal liver and the proportion of nuclei in the ploidy classes by inducing the premature formation of a significant population of tetraploids with a concomitant reduction in diploids. A great proportion of the replicative activity was present in tetraploid nuclei as measured by the incorporation of [3H] thymidine. The labeling index and number of mitoses were also increased. In contrast to DMN, mirex had no influence on polyploidization. The neonatal rats used in these studies thus offer an opportunity to investigate in vivo the mode of action of genotoxic versus epigenetic compounds with reference to their effect on DNA.

Animals↗
PubMed1985

Cloning and sequence of DNA encoding structural proteins of the autonomous parvovirus feline panleukopenia virus.

Approximately 80% of the genome of feline panleukopenia virus was cloned into pBR322. This DNA included the transcription unit for the major viral mRNA species. The nucleotide sequence of the cloned portion of the genome was determined. Comparison of the feline panleukopenia virus sequence with the sequences of the parvoviruses minute virus of mice and H-1 revealed considerable homology between the three viruses on both the nucleic acid and protein levels. Based on this homology, a model for the generation of the two size classes of viral structural proteins (VP1 and VP2') is proposed.

Amino Acid Sequence↗
PubMed1985

Chronic 'cryptogenic' liver disease and malignant hepatoma in intermediate alpha 1-antitrypsin deficiency identified by a Pi Z-specific monoclonal antibody.

Using a monoclonal antibody against the Pi Z genetic variant of alpha 1-antitrypsin in an enzyme-linked immunosorbent assay, we have screened plasma samples from 857 consecutive patients with liver disease for the presence of Pi Z alpha 1-antitrypsin. Intermediate alpha 1-antitrypsin deficiency (Pi MZ and SZ) was found in 64 cases, or 7.6%, compared with an expected 4.8% (p less than 0.001). The plasma alpha 1-antitrypsin level was subnormal in only 50% of them. Forty-three of the 64 heterozygotes were men, compared with 494 of 857 (58%) in the total study population (p less than 0.001). At least 14 heterozygotes had cryptogenic liver disease, compared with 3 of 128 sex- and age-matched controls from the same study population (p less than 0.001). Malignant hepatoma occurred in 6 heterozygotes compared with 1 control (p less than 0.01), and in 13 of all 793 non-Pi Z patients (p less than 0.001).

Antibodies, Monoclonal↗
PubMed1984

The relationship between distance from inpatient facilities and the rate of psychiatric admissions in Western Australia.

Western Australia is the largest and most sparsely populated state in Australia with all its specialised psychiatric inpatient facilities in Perth, the capital city. This study tested a number of hypotheses concerning the effect of distance from Perth, firstly, on total hospitalisation rates for psychiatric illness of the rural population and secondly, on the proportion who were hospitalized in Perth. High rates of alcoholism in males and of neuroses in females, together with local conditions in various rural centres, rather than distance from Perth, were major determining factors affecting both total hospitalisation and th proportion sent to Perth. The major exception was that the proportion of male alcoholics admitted to Perth hospitals decreased the further the patient lived from Perth. These findings were contrary to those reported in the literature. However the distances from Perth were much greater than those usually reported elsewhere. It was concluded that beyond a certain distance from psychiatric facilities, distance per se was not a major factor governing admissions to these facilities.

Alcoholism↗
PubMed1984

Reduction of digoxin effect during the digoxin-quinidine interaction.

The effects of the digoxin-quinidine interaction on cardiac function was examined in healthy subjects. Our results indicate that while serum digoxin levels were elevated, the improved cardiac function due to digoxin declined during combined therapy. Our data also provide an alternate explanation for the changes previously interpreted as "enhanced digitalis effects" during the interaction.

Adult↗
PubMed1984

Primary structure of the Escherichia coli ribonucleoside diphosphate reductase operon.

The nucleotide sequence of the Escherichia coli K-12 DNA comprising the operon for the structural genes of the subunits of ribonucleotide diphosphate reductase has been determined. The DNA sequenced maps at 48.5 minutes on the E. coli chromosome and includes a total length of 8557 nucleotides. An open reading frame between nucleotides 3506 and 5834, encoding a 776-amino acid polypeptide chain with a molecular weight of 87,532, has been identified as the nrdA gene. An open reading frame between nucleotides 6012 and 7139, encoding a 375-amino acid polypeptide with a molecular weight of 43,466, has been identified as the nrdB gene. The sequences reveal not only the primary structures for both subunits, but also some interesting aspects of potential regulatory sites.

Amino Acid Sequence↗
PubMed1984

Cloning and sequencing of the ribosomal RNA genes in maize: the 17S region.

The maize genes for the 17S, 5.8S, and 26S ribosomal RNAs (rRNAs) are located on chromosome 6 and consist of 9-kb sequences repeated about 5,000-10,000 times per 2C. One of these sequences was isolated from a lambda library containing maize Eco RI genomic segments. The sequence of the small-subunit (17S) RNA was determined using the M13 shotgun-dideoxy sequencing approach. The maize sequence was compared with nuclear rRNAs from yeast, Xenopus, and rat. Using these sequences, it is possible to identify tentatively the start and the end points of the sequence of the maize nuclear small subunit rRNA. This RNA has a length of 1809 nucleotides. The alignment of all four sequences for maximal homology allows us to identify regions within the rRNA that have been conserved during eukaryotic evolution.

Animals↗
PubMed1984

Amiloride potentiation of differentiation of human promyelocytic cell line HL-60.

Cells of the human acute promyelocytic cell line HL-60 undergo differentiation when exposed to dimethyl sulfoxide (DMSO); in this report, amiloride, an inhibitor of passive intracellular Na+ flux, potentiated the DMSO-induced differentiation of HL-60 cells. This effect was seen at several concentrations of DMSO. Amiloride alone did not affect HL-60 differentiation. Various analogues of amiloride were tested for their ability to potentiate differentiation of HL-60 cells. The synergistic induction of myeloid differentiation by a membrane solvent (DMSO) and an Na+ transport inhibitor (amiloride) suggested membrane cation flux as being important in initiating differentiation.

Amiloride↗
PubMed1984

Comparison of enzyme-linked immunosorbent assay, DNA hybridization, hemagglutination, and electron microscopy for detection of canine parvovirus infections.

Canine fecal samples were analyzed by enzyme-linked immunosorbent assays (ELISA) by using monoclonal antibodies to the canine parvovirus hemagglutinating protein. These data were compared with results obtained with DNA hybridization assays, hemagglutination assays, and electron microscopy. The highest correlation was observed between the ELISA and the hemagglutination tests, with 94.4% of samples showing agreement. Lower correlation was obtained between ELISA and DNA hybridization tests (73.3%). Correlation between ELISA and electron microscopy was 60.9%. The studies indicated that the ELISA can be used as a sensitive and specific diagnostic assay for canine parvovirus infections.

Animals↗
PubMed1984

Who treats in-patients with a primary psychiatric diagnosis?

Data are presented concerning all patients with a primary psychiatric diagnosis who were admitted to various hospitals in Western Australia during 1976-1978. Data were analysed, first, to ascertain the relative proportion of these patients who were admitted under psychiatrists and non-psychiatrists respectively; second, to compare the diagnoses of patients admitted under psychiatrists with those admitted under non-psychiatrists, and, third, to ascertain if there were any differences in terms of the first two measures between city and country patients. A high proportion of patients were admitted under non-psychiatrists. The majority of patients with a diagnosis of alcoholism, and a high proportion of patients with a diagnosis of neurosis, were admitted under non-psychiatrists. The majority of patients with a diagnosis of functional psychosis were admitted, under psychiatrists, to Mental Health Services hospitals and to psychiatric units at general teaching hospitals. Psychiatrists in private practice admitted mainly patients with a diagnosis of neurosis and personality disorder. The results are discussed in terms of the population distribution, the availability of psychiatric services and other factors which might influence the type of hospital to which patients are admitted and the type of doctor care they receive.

Adolescent↗
PubMed1983

The study of human myeloid differentiation using bromodeoxyuridine (BrdU).

Little is known concerning the mechanism of myeloid differentiation. A human promyelocytic cell line (HL-60) differentiates to granulocytes or macrophage-like cells when cultured with a variety of agents. How these agents trigger myeloid differentiation is not understood. This study shows that 1.0-10.0 micrograms/ml bromodeoxyuridine (BrdU) induced myeloid differentiation of HL-60 in liquid culture. After 7 days, BrdU (3.0 micrograms/ml) produced only moderate inhibition of HL-60 growth, but induced myeloid maturation with 40% of the cells becoming morphologically more mature; 41% developed the ability to reduce nitroblue tetrazolium (NBT); 19% phagocytized Candida albicans; and 18% developed Fc receptors. The action of BrdU was mimicked by 5-iodo-deoxyuridine. Thymidine (Td) (1- to 10-fold excess) competitively inhibited incorporation of [3H]BrdU into DNA of HL-60 and inhibited the triggering of HL-60 differentiation by BrdU. The BrdU-induced maturation of HL-60 correlated with the incorporation of BrdU into DNA of HL-60. DNA buoyant density studies showed that about 46% of the Td was replaced by BrdU in each DNA strand of HL-60 as the cells differentiated in culture containing 3 micrograms/ml BrdU for 7 days. We established 20 thymidine kinase (TK)-deficient HL-60 clones. The HL-60 TK-deficient cells were unable to phosphorylate Td, to incorporate either [3H]Td or [3H]BrdU or differentiate in the presence of BrdU (1-1000 micrograms/ml). The HL-60 TK-deficient cells retained the ability to differentiate in the presence of other HL-60 inducers. Taken together, the studies suggest myeloid differentiation of HL-60 is triggered because of incorporation of BrdU into DNA of the cells.

Bromodeoxyuridine↗
PubMed1983

Reversal and nonreversal shifts in autistic children.

Reversal and nonreversal shifts in nineteen 2- to 14-year-old autistic children were studied. Each child was taught both a reversal and nonreversal shift discrimination task. The reversal shift condition entailed teaching the child to respond to one (the S+) of a pair of stimuli during training and subsequently reversing the S+ during testing. The nonreversal shift condition consisted of teaching the child two unrelated discriminations during training and testing. The results indicated that the older autistic children did better on reversal shifts than younger children who did better on nonreversal shifts. These findings are consistent with those for normal children.

Adolescent↗