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Biomedical subjects

K Woodward

Publications and source records attributed to K Woodward.

17 recordsLinked to original sources
PubMed1995

Dihydroorotate dehydrogenase is a high affinity binding protein for A77 1726 and mediator of a range of biological effects of the immunomodulatory compound.

A protein with high affinity (Kd 12 nM) for the immunomodulatory compound A77 1726 has been isolated from mouse spleen and identified as the mitochondrial enzyme dihydroorotate dehydrogenase (EC 1.3.3.1). The purified protein had a pI 9.6-9.8 and a subunit Mr of 43,000. Peptides derived from the mouse protein displayed high microsequence similarity to human and rat dihydroorotate dehydrogenase with, respectively, 35 and 39 out of 43 identified amino acids identical. Dihydroorotate dehydrogenase catalyzes the fourth step in de novo pyrimidine biosynthesis. The in vitro antiproliferative effects of A77 1726 are mediated by enzyme inhibition and can be overcome by addition of exogenous uridine. The rank order of potency of A77 1726 and its analogues in binding or enzyme inhibition was similar to that for inhibition of the mouse delayed type hypersensitivity response. It is proposed that inhibition of dihydroorotate dehydrogenase is an in vivo mechanism of action of the A77 1726 class of compounds. This was confirmed using uridine to counteract inhibition of the murine acute graft versus host response.

Amino Acid Sequence↗
PubMed1995

Regional localization of 64 cosmid contigs, including 18 genes and 14 markers, to intervals on human chromosome 9q34.

A fluorescence in situ hybridization map of distal human chromosome 9q has been produced by mapping cosmid clones to metaphase chromosomes with balanced reciprocal translocations. This is a very accurate method of mapping, as clones are localized by their position with respect to the breakpoint in addition to cytogenetic banding. By using three lymphoblastoid cell lines with translocation breakpoints within 9q34, we have localized 18 genes and 14 DNA markers to one of four intervals on the chromosome. Cosmid contigs exist around 16 of these genes and 12 of these markers. A further 43 contigs have also been mapped, but they are as yet anonymous.

Animals↗
PubMed1995

Comparative mapping of 50 human chromosome 9 loci in the laboratory mouse.

We have set out to produce a comprehensive comparative map between human chromosome 9 (HSA9) and the laboratory mouse. The mouse homologues of 50 loci that were known to map to HSA9 were mapped by interspecific backcross linkage analysis. Ten loci from the short arm of HSA9 were mapped, and 40 from HSA9q, with 24 markers coming from the HSA9q33-q34 region--a part of the chromosome known to be very gene rich. Fifteen new assignments have been made--Ak3, Ctsl, Cntfr, C8g, D2H9S46E, Eng, Gcnt1, Irebp, Pappa, Ptgds, Snf212, Tal2, Tmod, Vav2, and Vldlr, the human homologues of which all map to HSA9. In addition, the assignment of Snf212 and Vldlr to MMU19 has defined a new region of synteny between the proximal portion of the short arm of HSA9 and the mouse.

Animals↗
PubMed1995

Cosmid contigs spanning 9q34 including the candidate region for TSC1.

The tuberous sclerosis disease gene TSC1 has been mapped to 9q34. However, its precise localisation has proved problematic because of conflicting recombination data. Therefore, we have attempted to clone the entire target area into cosmid contigs prior to gene isolation studies. We have used Alu-PCR from irradiation hybrids to produce complex probes from the target region which have identified 1,400 cosmids from a chromosome-specific library. These, along with cosmids obtained by other methods, have been assembled into contigs by a fingerprinting technique. We estimate that we have obtained most of the region in cosmid contigs. These cosmids are a resource for the isolation of expressed genes within the TSC1 interval. In addition, the cosmid contig assembly has demonstrated a number of previously unknown physical connections between genes and markers in 9q34.

Animals↗
PubMed1994

Genomic cloning and localization by FISH and linkage analysis of the human gene encoding the primary subunit NMDAR1 (GRIN1) of the NMDA receptor channel.

A cDNA clone of the NMDAR1 (isoform E) has been used to screen both lambda and cosmid genomic libraries. A genomic phage clone was identified and sequenced and was found to contain some of the 3' coding regions of the GRIN1 gene. This clone was used to localize the gene using fluorescent in situ hybridization (FISH) to normal chromosomes, and also to a lymphoblastoid cell line containing a translocation involving chromosomes 9 and 15. FISH localized the gene to chromosome 9q34.3. The clone was used to screen a panel of genomic DNAs cut with 20 restriction enzymes. A VNTR sequence 5' to the gene, which was polymorphic for a number of restriction enzymes, was detected. A PvuII fragment of the genomic clone was found to detect the VNTR on Southern hybridization. The polymorphic VNTR marker was mapped against chromosome 9q34 markers using linkage analysis in the CEPH families. The GRIN1 gene was linked to D9S7 with a maximum lod score of 20.09 at zero recombination fraction in males and 0.03% recombination in females.

Alleles↗
PubMed1991

Differential auditory processing continues during sleep.

Auditory evoked potentials (AEPs) were used to examine selective stimulus processing in sleep. In waking, repetitive stimuli generate exogenous P1, N1 and P2 components of the auditory evoked potential (AEP). Deviant stimuli generate endogenous cognitive components including the mismatch negativity (MMN), N2 and P3 components. We examined long-latency auditory evoked potentials elicited by repetitive and deviant stimuli during waking and stage II-IV sleep to assess whether stimulus deviance is detected during sleep. The waking P1, N1b and P2 had maximal amplitudes at fronto-central scalp sites, with additional peaks (N1a, N1c) at temporal sites. Deviant tones generated a frontal maximal MMN, and complex novel tones generated an additional P3 component maximal at centro-parietal sites. During stages II-IV sleep N1a, b, c amplitudes were reduced. During stage II sleep all stimuli generated increased P2 amplitudes and a late negative component (N340). Deviant stimuli generated greater P2 and N340 amplitudes than frequent stimuli in stage II sleep, as well as an additional P420 component. In stage III-IV sleep the P420 was absent and the AEP was dominated by a negativity of long duration whose amplitude increased in response to deviant stimuli. These data indicate that auditory evoked activity changes from wakefulness to sleep. The differential response to deviant sounds observed during waking and all sleep stages supports the theory that selective processing of auditory stimuli persists during sleep.

Adolescent↗
PubMed1987

Diagnosing gonorrhea. A comparison of standard and rapid techniques.

A timely and accurate technique for diagnosing gonorrhea is necessary if prompt therapy is to be instituted. We screened 567 adolescents who presented for routine gynecologic care or for specific gynecologic or urologic problems. Each patient was tested by standard culture, Gonozyme (Abbott Labs), and Gram's stain. One hundred five patients (18.5%) had an ELISA immunoassay or culture evidence of infection. Overall sensitivity was 90% for Gonozyme and 56% for Gram's stain (females 41%, males 94%). Overall specificity was 97% for Gonozyme and 99% for Gram's stain. No increase in sensitivity of either test was found in women with signs of upper genital tract involvement. The predictive value of a negative Gonozyme was 98% and 85% for a positive result compared to Gram's stain values of 99% and 95%, respectively. Overall clinical efficacy was 96% for Gonozyme and 93% for Gram's stain. Gonozyme, although a sensitive and specific test, has a limited role in the diagnosis of gonorrhea. Gram's stain, although more limited in women, may serve as a useful adjunct in diagnosing gonorrhea.

Adolescent↗
PubMed1982

Inhibition of phorbol ester-receptor binding by a factor from human serum.

The inhibition of receptor binding of [3H]phorbol-12,13-dibutyrate (PDBu) by a factor from human serum was characterized. The serum factor inhibited [3H]PDBu binding in intact monolayer cultures of the rat embryo cell line CREF N and in a subcellular system containing membranes from these cells. Inhibition occurred at both 37 and 4 degrees C and was rapid and reversible. An analysis of [3H]PDBu binding in the presence of the serum factor indicated that inhibition of [3H]PDBu binding by the serum factor was noncompetitive. Using gel filtration to separate the serum factor from free [3H]PDBu, we obtained evidence that the serum factor does not act by binding or trapping the [3H]PDBu. Unlike the phorbol ester tumor promoters, the serum factor alone did not stimulate the release of choline or arachidonic acid from cellular phospholipids, nor did it inhibit the binding of 125I-labeled epidermal growth factor to cellular receptors. The factor did, however, antagonize the inhibition of epidermal growth factor binding induced by PDBu. Sera from pregnant women were, in general, more inhibitory of [3H]PDBu binding than were those from nonpregnant women, which were more inhibitory than those from men. During these studies we found that CREF N cells responded to being grown in the presence of PDBu by partial down regulation of the phorboid receptor. The 50% effective dose for down regulation was 8 nM PDBu, and the maximum effect occurred after 6 h. Taken together, our results indicate that the serum factor inhibits [3H]PDBu binding by a direct physical effect at the level of the phorboid receptors or their associated membranes. It would appear that if this factor acts in vivo, then it might antagonize certain effects of this class of tumor promoters.

Animals↗
PubMed1981

New HLA-D alleles associated with DR1 and DR2.

The present study describes two new HLA-D specificities : LD 13, associated with DR1, and LD14 associated with DR2. LD13 is defined by an HTC who is the bc offspring of an a: A25, B18, DR7, Dw7/b: A33, B14, DR1, Dx father, and of a c: A24, B14, Dr1, Dx/d: A26, B41, DR5, Dw5 mother. This HTC was included both as a responder and as a stimulator in our cross-reference studies of 8W HTCs. While failing to cluster with any other 8W HTC, it typed 2 of 64 panel members carrying a "blank" HLA-D, linked to DR1. To exclude the possibility that HTC-LD13 might be a split of Dwl, the entire family was tested with the Family Set of 8W HTCs. No typing responses to any 8W Dw1 HTCs were observed. Furthermore, checkerboard experiments between HTC-LD13 and 8WDw1 HTCs showed strong reciprocal stimulation. The LD13 specificity was only found in Ashkenazi Jews and may be in linkage disequilibrium with HLA-B14. LD14 is defined by three, SD different, HTCs deriving from the same family of Sicilian descent. The family was included in the 8th Workshop and each HTC was shown to have inherited DR2, MT1 from both parents. When tested as stimulators, on our HLA-D reference panel, these cells were clustered in a distinct group, LD14, associated with DR2. None of the 8W HTCs appeared to belong to this cluster. The antigen frequency of LD14 is 0.03.

Alleles↗