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Biomedical subjects

C R Wood

Publications and source records attributed to C R Wood.

34 records · Page 2Linked to original sources
PubMed1993

Planimetric rate of healing in venous ulcers of the leg treated with pressure bandage and hydrocolloid dressing.

BACKGROUND: Venous leg ulcers are a common cause of morbidity, but few predictive parameters exist that can be used to follow their progress. OBJECTIVE: We investigated the use of healing rate as a useful parameter in the treatment of venous ulceration. METHODS: Twenty-seven venous ulcers being treated with a standard regimen were evaluated. We calculated the initial (4-week) and overall healing rates using the Gilman method (delta A/p). RESULTS: The average initial healing rate for all ulcers combined, the healed group, and the nonhealing group was 0.069, 0.087, and -0.005 cm/wk, respectively. Similarly, the average overall healing rate for all ulcers combined, the healed group, and the nonhealing group was 0.062, 0.089, and -0.043 cm/wk, respectively. CONCLUSION: The initial healing rate (delta A/p(0-4)) may be an appropriate end point for clinical investigations comparing therapies for the treatment of chronic venous leg ulcers.

Bandages↗
PubMed1993

Venous leg ulcers: an analysis of underlying venous disease.

Patients with venous leg ulcers have a readily recognized clinical syndrome of shallow ulcers, oedema, leg pain, venous ankle blush, lipodermatosclerosis, varicose veins, hyperpigmentation, and atrophie blanche, and they are assumed to have venous abnormalities. We examined 43 patients with venous leg ulcers, and compared those with obvious venous abnormalities (defined as historical or clinical evidence of deep venous thrombosis or varicose veins) with those with presumed venous abnormalities (defined as lacking any such evidence), to see if they presented with different clinical features. We found that both groups had similar clinical features, with the exception that lipodermatosclerosis was present more frequently in those patients with obvious venous abnormalities (94 vs. 36%, P < 0.001). Most patients with presumed venous abnormalities had musculoskeletal conditions which might cause calf pump dysfunction (91%). Using air plethysmography, we were unable to confirm that all patients with presumed venous abnormalities did have intrinsic venous abnormalities. We propose that ulcers occurring in this clinical syndrome be designated as calf pump dysfunction ulcers (CPD ulcers), rather than venous ulcers.

Arteriosclerosis↗
PubMed1993

Molecular cloning of murine FLT and FLT4.

A wide range of growth and differentiation processes are regulated by the signalling of receptor tyrosine kinases (RTKs). We have developed a nested polymerase chain reaction (PCR) procedure with degenerate primers, and used it to identify RTKs expressed in murine fetal thymus. A novel RTK, called FLT4, and the murine homologue of FLT were found, and their PCR fragment sequences were used to isolate larger cDNA clones spanning the complete coding regions of these receptors. FLT4 was found to contain an extracellular region similar to the corresponding sequences of FLT and Flk-1, containing seven immunoglobulin domains.

Amino Acid Sequence↗
PubMed1992

Molecular cloning of the cDNA encoding a receptor tyrosine kinase-related molecule with a catalytic region homologous to c-met.

Receptor tyrosine kinases mediate a range of growth and differentiation processes in multiple biological systems. In this work, we report the identification of a novel tyrosine kinase-related molecule, nyk-r, and the molecular cloning of its complete cDNA. Its extra-cellular domain bears no apparent homology with other receptor families, but its intracellular kinase-related region has considerable similarity with members of the insulin-receptor family such as c-met and trk B. Also, the nyk-r gene is expressed in a wide range of tissues and cell lines.

Amino Acid Sequence↗
PubMed1991

An internal ribosome binding site can be used to select for homologous recombinants at an immunoglobulin heavy-chain locus.

The encephalomyocarditis virus (EMCV) leader sequence is responsible for efficient, cap-independent translation initiation from the viral RNA. It has been used to increase the expression of internal coding regions on polycistronic mRNA encoded by recombinant DNA constructs. We have designed a sequence-replacement-type vector for targeting to immunoglobulin heavy-chain loci in hybridoma cells. Homologous recombination of this vector introduces a human gamma 1 constant-region sequence linked to the EMCV leader and a neomycin phosphotransferase (neo) gene. The resulting cells express a bicistronic mRNA encoding at the 5' end a chimeric murine VDJH-human C gamma 1 heavy chain, followed by neo linked to the internal ribosome binding site provided by the EMCV leader. These homologous recombinants express the chimeric heavy chain at levels equivalent to the heavy chain in the parental hybridoma. This strategy of using an EMCV-neo cassette to obtain efficient selectable marker gene expression has potential application to a range of gene targeting vectors.

Animals↗
PubMed1990

High level synthesis of immunoglobulins in Chinese hamster ovary cells.

The expression of lambda L and microH chain cDNA was examined in Chinese hamster ovary cells. Each cDNA was linked to a different, amplifiable, selectable drug marker gene, and expression was monitored in the presence of increasing concentrations of the selective drugs. Cells were obtained that produced greater than 60 micrograms/10(6) cells/48 h of assembled antibody. This Chinese hamster ovary cell-synthesized IgM was polymeric, and exhibited specific hapten binding and C fixation. The expression strategy employed here may prove useful for the future production of genetically engineered antibodies and other multi-subunit proteins.

Animals↗
PubMed1990

Molecular cloning of a cDNA encoding interleukin 11, a stromal cell-derived lymphopoietic and hematopoietic cytokine.

Hematopoiesis occurs in close association with a complex network of cells loosely termed the hematopoietic microenvironment. Analysis of the mechanisms of microenvironmental regulation of hematopoiesis has been hindered by the complexity of the microenvironment as well as the heterogeneity of hematopoietic stem cells and early progenitor cells. We have established immortalized primate bone marrow-derived stromal cell lines to facilitate analysis of the interactions of hematopoietic cells with the microenvironment in a large animal species. One such line, PU-34, was found to produce a variety of growth factors, including an activity that stimulates the proliferation of an interleukin 6-dependent murine plasmacytoma cell line. A cDNA encoding the plasmacytoma stimulatory activity was isolated through functional expression cloning in mammalian cells. The nucleotide sequence contained a single long reading frame of 597 nucleotides encoding a predicted 199-amino acid polypeptide. The amino acid sequence of this cytokine, designated interleukin 11 (IL-11), did not display significant similarity with any other sequence in the GenBank data base. Preliminary biological characterization indicates that in addition to stimulating plasmacytoma proliferation, IL-11 stimulates the T-cell-dependent development of immunoglobulin-producing B cells and synergizes with IL-3 in supporting murine megakaryocyte colony formation. These properties implicate IL-11 as an additional multifunctional regulator in the hematopoietic microenvironment.

Amino Acid Sequence↗
PubMed1986

A sensitive, nondestructive assay for transfected genes.

We have adapted the fibrin overlay assay for plasminogen activators (Jones et al., 1975) into a gene transfer expression assay which has the advantage of being very sensitive and nondestructive. In this assay plasminogen activators convert plasminogen to plasmin, which then degrades fibrin, resulting in clearings in a fibrin overlay. Furthermore, the assay can be used as a signal indicating the efficiency of gene transfer or the loss of introduced genetic elements in unstable cell lines.

Acetyltransferases↗
PubMed1984

Assembly of functional antibodies from immunoglobulin heavy and light chains synthesised in E. coli.

Genes for a murine mu heavy chain and a lambda light chain immunoglobulin have been inserted into bacterial expression plasmids containing the Escherichia coli trp promoter and ribosome binding site. Induction of transcription from the trp promoter results in accumulation of both light and heavy chain polypeptides in appropriate host strains. Both proteins were found as insoluble products. Following extraction and purification of the immunoglobulin containing fractions, antigen binding activity was recovered. The activity demonstrates essentially the same properties as the antibody from the hybridoma from which the genes were cloned.

Animals↗
PubMed1984

The influence of messenger RNA secondary structure on expression of an immunoglobulin heavy chain in Escherichia coli.

A gene for murine mu heavy chain immunoglobulin has been inserted into a bacterial expression plasmid containing the Escherichia coli trp promoter and ribosome binding site. A low level expression of mu protein was detected. Secondary structure analysis showed the presence of a hairpin loop burying the mu initiation codon. Alteration of secondary structure at this site by oligonucleotide replacement mutagenesis revealed a correlation between mu expression levels and accessibility of the ribosome binding site. Abolition of secondary structure increased mu protein expression over ninety-fold, to a level approximately equal to that of a trpE -mu fusion protein using the native trpE ribosome binding site.

Animals↗
PubMedDate not supplied

Metkephamid effects on operant behavior.

Intravenous injections of high doses of metkephamid (20 and 40 mg/kg) decreased responding by pigeons under a multiple fixed-ratio, fixed-interval schedule of grain presentation. Naloxone antagonized in a dose-related manner the suppression of behavior produced by 40 mg/kg of metkephamid. Daily maintenance on large doses (30 and 60 mg/kg PO) of dlmethadone produced a slight shift of the dose-effect curve of metkephamid to the right. The data suggest that the behavioral effects of metkephamid are due to an action at a mu-opioid receptor.

Animals↗
PubMedDate not supplied

The synthesis and in vivo assembly of functional antibodies in yeast.

The yeast Saccharomyces cerevisiae can synthesize, process and secrete higher eukaryotic proteins. We have investigated the expression of immunoglobulin chains in yeast and demonstrate here the synthesis, processing and secretion of light and heavy chains, the glycosylation of heavy chain, the intracellular localization of these foreign proteins by immunofluorescence, and the detection of functional antibodies in cells co-expressing both chains. This may provide the basis of a microbial fermentation process for the production of monoclonal antibodies. The co-expression of light and heavy chains in Escherichia coli has been reported but functional antibodies were not assembled in vivo. Furthermore, only low-level assembly of these chains was found in vitro.

Antibodies, Fungal↗