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Biomedical subjects

J M Buchanan

Publications and source records attributed to J M Buchanan.

At least 19 recordsLinked to original sources
PubMed1992

Expression of a human chimeric transferrin gene in senescent transgenic mice reflects the decrease of transferrin levels in aging humans.

Transgenic mice provide a means to study human gene expression in vivo throughout the aging process. A DNA sequence containing 668 bp of the 5' regulatory region of the human transferrin gene was fused to the bacterial reporter gene chloramphenicol acetyl transferase (TF-CAT) and introduced into the mouse genome. Expression of the human chimeric transferrin gene was similar to the tissue patterns of mouse and human transferrin. In aging transgenic mice, expression of the human chimeric transferrin gene was found to diminish 40% in livers between 18 and 26 months of age. Transferrin levels and serum iron levels in aging humans also diminish, as observed from measurements of total iron binding capacity and percent iron saturation in sera from 701 individuals ranging from 0 to 99 years of age. In contrast, in transgenic mice and nontransgenic mice, the mouse endogenous plasma transferrin and endogenous Tf mRNA increase significantly during aging. Neither the decrease of human TF-CAT nor the increase of mouse transferrin during aging appears to be part of a typical inflammatory reaction. Although the 5' regions of the human transferrin and mouse transferrin genes are homologous, sequence diversities exist which could account for the different responses to inflammation and aging observed.

Adolescent↗
PubMed1990

Expression of transferrin and vitamin D-binding protein genes in an osteogenic sarcoma cell line.

Expression of genes encoding transferrin and the vitamin D-binding protein is described in a cell line, U-2 OS, derived from a human osteogenic sarcoma. The mRNA transcripts of transferrin and vitamin D-binding protein were shown to be the lengths of those found in normal human liver. The cells synthesize and secrete the transferrin and vitamin D-binding proteins, in addition to human albumin and ceruloplasmin. The U-2 OS cells were successfully transfected with chimeric genes carrying 670 bp of the 5' regulatory sequence of the human transferrin gene fused to a reporter chloramphenicol acetyltransferase gene. These data indicate that the appropriate transcriptional factors required for expression of four plasma proteins are produced by U-2 OS nuclei and that the U-2 OS cell line will be useful for studies analyzing regulation of these genes.

Ceruloplasmin↗
PubMed1990

Tissue specific expression of mouse transferrin during development and aging.

Transferrin (TF) is a major plasma protein that binds ferric iron and transports it to all target tissues of the body. This study is the first step to identify the tissue specific expression of the transferrin gene in mice during development, into maturity and throughout the aging process. The transferrin gene expresses mainly in mouse liver, the cerebral hemispheres and cerebellum. In mouse, transferrin is expressed in peritoneal macrophages and in mouse macrophage cell line MO59. At 19 days of gestation, transferrin mRNA is detected in the fetal lung, heart, stomach and kidney. TF mRNA levels increase in liver throughout gestation with maximum expression occurring at 19 days. Transferrin mRNA was detected in placentas of pregnant mice, with levels progressively increasing throughout the term of pregnancy. The levels of liver TF mRNA in mouse vary in a cyclic manner during the development increasing with the aging processes. Because of the dynamic nature of tissue requirements for transferrin during homeostasis the TF gene serves as a promising system for analyzing tissue-specific regulation in vivo during development and aging. Results from this study designate periods in the life-span of the mouse where regulatory mechanisms interacting with the TF gene appear to dynamically alter its expression.

Aging↗
PubMed1989

Human interleukin 3: effects on normal and leukemic cells.

The effects of recombinant human interleukin 3 (IL3) on normal bone marrow cells and human leukemic cells were studied. In clonal assays, IL3 supported the growth of all colony types including megakaryocytes. Erythroid colonies were formed in the presence of IL3 and erythropoietin, but not in the absence of erythropoietin. Replating experiments using blast cell colonies derived from a cell population enriched for progenitor cells by fluorescence-activated cell sorting with the monoclonal antibody 3C5, showed that IL3 supported the continued replating of colonies. The clonal proliferation of human bone marrow cells in response to IL3 was inhibited by tumor necrosis factor and by lymphotoxin, but not by interferon-gamma. In suspension cultures, IL3 supported the proliferation of mast cells. Human IL3 had no effect on the growth responses, morphology, cytochemistry, or clonogenicity of the human leukemic cell lines HL60, U-937, KG1a, and HEL. Transcripts for IL3 mRNA were not detectable in these cells, nor in the K562 cell line, implying that autocrine secretion of IL3 was not the mechanism by which these leukemias were maintained. Although cells derived from the bone marrow or peripheral blood of twenty patients with myeloproliferative disorders, myelodysplastic syndromes or acute myeloid leukemia frequently showed proliferative responses to IL3, mRNA transcripts for IL3 were not detected in these cells.

Blood Cells↗
PubMed1988

Postoperative pain relief; a new approach: narcotics compared with non-steroidal anti-inflammatory drugs.

The pain relief provided by regular intramuscular diclofenac and on demand intramuscular papaveretum was compared over a 48 h postoperative period in 114 patients undergoing total hip replacement. The study was of a randomised, single-blind, between-group design. Patients were assessed by a surgeon, physiotherapist and nursing staff. Diclofenac was more effective than papaveretum in pain control (P less than 0.001), wound tenderness (P less than 0.01), awareness (P less than 0.001) and mobilisation (P less than 0.01). Wound drainage (P greater than 0.05) and wound oedema (P greater than 0.05) were not significantly different in the two treatments. Gastrointestinal complications were encountered in both groups; two patients on diclofenac had to be withdrawn because of them. The use of diclofenac given as a postoperative analgesic is rewarding, particularly in patients undergoing musculoskeletal procedures. Patients will be more comfortable and will mobilise better during their whole postoperative course.

Aged↗
PubMed1987

A controlled prospective study of early mobilization of minimally displaced fractures of the distal radial metaphysis.

A controlled prospective trial of early exercise of slightly displaced fractures of the distal radial metaphysis has been performed. Twenty-eight fractures were enclosed in a tubigrip support 7-13 days after injury and 28 fractures were splinted in below-elbow plaster for 4 weeks. It was found that early movement of the wrist produced a superior functional result at 5 and 7 weeks (P less than 0.05) and allowed an earlier recovery of domestic skills (P less than 0.05). Early exercise did not improve recovery of strength of grip and did not produce a higher incidence of malunion. Patients treated in tubigrip experienced no more pain in weeks 4 and 6 and apart from one failure, no patient actively disliked this form of treatment and 22 were totally satisfied.

Aged↗
PubMed1986

Phosphorylation of tyrosine in the carboxyl-terminal tryptic peptide of pp60c-src.

The major site of tyrosine phosphorylation of the transforming protein of Rous sarcoma virus, pp60v-src (tyrosine-416), is different from the major site of tyrosine phosphorylation of its nontransforming normal cellular counterpart, pp60c-src. We have shown that antibodies against a synthetic peptide modeled on the carboxyl-terminal 13 residues of pp60c-src specifically immunoprecipitate the major phosphotyrosine tryptic peptide of pp60c-src from both chicken and rat fibroblasts. These experiments localize the major site of tyrosine phosphorylation to one or more of the three tyrosine residues in the carboxyl-terminal tryptic peptide at positions 511, 519, and 527 of the amino acid sequence of chicken pp60c-src. Tyrosines-519 and -527 are in the carboxyl-terminal 19-amino acid segment of pp60c-src that is deleted and replaced by an unrelated sequence in pp60v-src. It is possible that phosphorylation of tyrosine in the carboxyl-terminal tryptic peptide may be involved in the normal regulation of pp60c-src. The absence of this phosphorylation site in pp60v-src may, in part, contribute to its oncogenic properties.

Animals↗
PubMed1986

Linkage of cystic fibrosis locus and polymorphic DNA markers in 14 families.

Linkage relationships between the cystic fibrosis (CF) locus and three polymorphic DNA markers were examined in 14 families, five of which were of Hispanic origin. Tight linkage was found between the CF locus and MET (maximum lod score = 7.16 at theta = .001), and between CF and pJ3.11 (maximum lod score = 3.87 at theta = .001). We observed two recombinations between CF and collagen, yielding a maximum lod score of 0.359 at theta = .125, and one recombination in the cluster CF-MET-pJ3.11. Analysis by the seriation method indicates the order COL-pJ3.11-CF-MET.

Cystic Fibrosis↗
PubMed1979

Equilibrium: the intracellular distribution of steroid receptors.

Data are presented which suggest that there are unbound receptors for oestrogen in nuclei of the smooth muscle cells of the myometrium. A new model for the distribution of unbound receptors is proposed in which unbound receptor is in equilibrium, partitioned between nucleus and cytoplasm according to the free water content of these intracellular compartments.

Animals↗
PubMed1979

The arthritic in an urban environment.

Ninety-five patients with rheumatoid arthritis or osteoarthrosis were interviewed and questioned in their homes, being randomly selected from 354 outpatients with these diseases. The findings were compared with answers from 30 matched able-bodied controls. The handicapped were mainly female and elderly; over half were severely or appreciably handicapped; nearly one-third lived alone. The average weekly income of these households was pound25, at least pound6 a week less than their age-matched counterparts. Very few subjects lived in adapted or specially designed housing, and half the housing had at least 2 steps to street level. A third of the sample could not walk more than 10 yards (9 m), and only half could walk 100 yards (90 m); yet only one-third had a bus stop, one-quarter a local park, and one-third a local shop within this distance. One-third of the patients could not shop for themselves. Powered wheelchairs were not used. Buses were rarely or never used by nearly half these arthritics because of severe disability. Cars were owned by less than a quarter of the sample, and only by those financially better off. Over a third were unable to get a lift when wanted. Cars ameliorated much of the frustration and lack of social contact caused by physical disability. Adequate financing would enable those with severe disability to engage in normal activities. Better designed buses stopping nearer the homes of handicapped would improve independence for those less severely disabled. Correct siting of mobility housing, shops, community facilities, and parks would be greatly appreciated, as would removal of all unnecessary steps and kerbs.

Adult↗
PubMed1978

Multiple forms of sarc gene proteins from Rous sarcoma virus RNA.

In a previous study we were able to identify two proteins of 25,000 and 18,000 daltons that were made from RNA of transforming virions of Rous sarcoma virus (RSV) and that were missing from the translation products of a transformation-defective deletion mutant of RSV. In the present study we have separated RSV virion RNA on sucrose gradients and have determined that the two putative sarc gene products are synthesized as doublets from an mRNA of approximately 18 S. There also appear to be several other sizes of virion mRNA that direct the synthesis of other viral proteins. These data are discussed in terms of the structure of the RSV genome. In addition to the 25,000- and 18,000-dalton doublets, there also is a 60,000-dalton protein whose synthesis is directed by 18S viral RNA from transforming virion of RSV. Peptide mapping has shown that the 60,000- and 25,000-dalton doublet are structurally related. In addition, the use of two-dimensional gel electrophoresis has allowed us to resolve both bands of the 25,000-dalton doublet into several differently charged species.

Amino Acids↗
PubMed1978

Processing of 60,000-dalton sarc gene protein synthesized by cell-free translation.

In this report we show that antiserum prepared against the Mr60,000 transformation-specific antigen of Rous sarcoma virus immunoprecipitates both the Mr60,000 and Mr 25,000 transformation-specific proteins that are synthesized by cell-free translation of virion RNA; however, in the cell-free system the Mr 60,000 protein appears to be synthesized as a precursor that is approximately Mr 2000 larger than the [35S]-methionine-labeled protein immunoprecipitated from Rous sarcoma virus-infected cells. Peptide mapping of the cell-free translation product and of this cellular protein has confirmed that they are structurally related to one another. The addition of membrane vesicles to the reticulocyte lysate system during translation specifically cleaves a Mr 2000 segment from the Mr 60,000 protein so that it comigrates with the cellular species. Secretory proteins and probably at least some integral membrane proteins are synthesized with short hydrophobic signal sequences at their NH2 terminus. Two facts suggest that the segment lost from the Mr 60,000 transformation-specific protein is a signal sequence: (i) the membrane vesicles process the Mr 60,000 protein only during translation, and (ii) the processed protein is sequestered by the vesicles.

Amino Acid Sequence↗
PubMed1977

Initiation of synthesis of messenger RNA of deoxynucleotide kinase by oligoribonucleotides.

The effects of nucleoside triphosphates and oligoribonucleotides on the initiation of synthesis of messenger RNA of the T4 phage-specific enzyme, deoxynucleotide kinase, have been studied. The procedure involved incubation of T4 DNA, purified RNA polymerase from Escherichia coli, and selected nucleotide compounds during a brief period to permit initiation of RNA synthesis. Further initiation was arrested by the addition of ribampicin, and completion of the transcription of the newly initiated RNA was permitted to take place in the presence of the full complement of nucleoside triphosphates. After translation of the messenger RNA into phage-specific enzymes, the measured activities of the latter whe first incubation period. The effectiveness of individual nucleoside triphosphates, when present singly or in combination during the initiation period, was compared to that when all four nucleoside triphosphates were available. ATP alone was extremely effective as an initiator of the synthesis of the messenger RNA for deoxynucleotide kinase. The addition of UTP to ATP not only enhanced the magnitude of initiation but also affected the kinetics of ATP interaction with T4 DNA and RNA polymerase during the initiation period. Several oligoribonucleotides including a series ApA to ApApApA, UpU to UpUpUpU, and the heteropolymers, Ap1pU and ApApApU, were tested as initiators of kinase mRNA synthesis. A sequence of nucleotides in the promoter region of T4 DNA for the deoxynucleotide kinase gene has been proposed as a result of these experiments.

Adenosine Triphosphate↗