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Biomedical subjects

D J Perry

Publications and source records attributed to D J Perry.

At least 37 records · Page 2Linked to original sources
PubMed1999

Mechanism of action of interferon-tau in the uterus during early pregnancy.

Early pregnancy is maintained in ruminants through the actions of conceptus-derived interferon (IFN)-tau on the endometrium. IFN-tau alters uterine release of PGF2 alpha' which results in rescue of the corpus luteum and continued release of progesterone. The mechanism of action of IFN-tau includes inhibition of oestradiol receptors, consequent reduction in oxytocin receptors, activation of a cyclooxygenase inhibitor, and a shift in the PGs to favour PGE2 over PGF2 alpha' IFN-tau also induces several endometrial proteins that may be critical for survival of the developing embryo. One endometrial protein induced by pregnancy and IFN-tau has been identified as bovine granulocyte chemotactic protein-2 (bGCP-2). This chemotactic cytokine (chemokine) has been used as a marker to delineate IFN-tau from IFN-alpha responses in the endometrium. A second protein, called ubiquitin cross-reactive protein (UCRP), resembles a tandem ubiquitin repeat. UCRP becomes conjugated to cytosolic endometrial proteins in response to IFN-tau and pregnancy. Proteins conjugated to UCRP are either modulated or targeted for processing through the proteasome. The action of IFN-tau is mediated by induction of signal transducer and activator of transcription 1 (STAT-1), STAT-2 and interferon regulatory factor 1 (IRF-1) transcription factors. Induction of these transcription factors, the alpha chemokines and UCRP is the prelude to maternal recognition of pregnancy in ruminants.

Amino Acid Sequence↗
PubMed1998

Clinical experience with the use of clotting factor concentrates in oral anticoagulation reversal.

We report the clinical experience of a large Haemophilia Centre and Haemostasis Unit in reversing oral anticoagulation (OAC) using clotting factor concentrates. This is a retrospective study extending over 2 years (January 1996-December 1997). Reversal was performed using a combination of factor IX and factor VII concentrates administered by intravenous infusion. in a dose varying between 12 i.u./kg and 50 i.u./kg. We identified 20 episodes of OAC reversal in 18 patients, with a prevalence of 10 reversal episodes/1000 OAC patients/year. The median age was 77 years old (range 53-92 years). Indications for OAC reversal were divided into major bleeds (muscle haematoma [9], haematuria [3], subarachnoid haemorrhage [1], oesophageal bleeding [1], haemoptysis [1], haemarthrosis [1]); minor bleeds (extensive bruising [9], epistaxis [3], oral cavity bleeding [1]); and emergency invasive investigation (2). Pre-reversal, the international normalized ration (INR) was greater than 6.0 in 15/18 patients. Post-infusion. there was an immediate reduction in the INR towards normal (mean 1.3; range 1.1-2.3). There were no thrombotic complications or other adverse effects. The median use of factor 9 A concentrate was 2300 units/patient (range 570-4195), at a cost of 645 Pounds/patient and for factor VII concentrate 2200 units/patient (range 815-3630), at a cost of 664 Pounds/patient. Clotting factor concentrates provide a safe, rapid and effective means for OAC reversal and although expensive it is the treatment of choice in the over anticoagulated, bleeding patient.

Aged↗
PubMed1998

Sequence-tagged-site (STS) markers of arbitrary genes: development, characterization and analysis of linkage in black spruce.

Sequence-tagged-site (STS) markers of arbitrary genes were investigated in black spruce [Picea mariana (Mill.) B.S.P.]. Thirty-nine pairs of PCR primers were used to screen diverse panels of haploid and diploid DNAs for variation that could be detected by standard agarose gel electrophoresis without further manipulation of amplification products. Codominant length polymorphisms were revealed at 15 loci. Three of these loci also had null amplification alleles as did 3 other loci that had no apparent product-length variation. Dominant length polymorphisms were observed at 2 other loci. Alleles of codominant markers differed in size by as little as 1 bp to as much as an estimated 175 bp with nearly all insertions/deletions found in noncoding regions. Polymorphisms at 3 loci involved large (33 bp to at least 114 bp) direct repeats and similar repeats were found in 7 of 51 cDNAs sequenced. Allelic segregation was in accordance with Mendelian inheritance and linkage was detected for 5 of 63 pairwise combinations of loci tested. Codominant STS markers of 12 loci revealed an average heterozygosity of 0.26 and an average of 2.8 alleles in a range-wide sample of 22 trees.

Alleles↗
PubMed1998

Alpha1-antitrypsin deficiency alleles and the Taq-I G-->A allele in cystic fibrosis lung disease.

Cystic fibrosis (CF) is characterized by progressive and ultimately fatal pulmonary disease although there are notable variations in clinical features. This heterogeneity is thought to lie outside the cystic fibrosis transmembrane regulator (CFTR) gene locus and may stem from deficiencies in the antiproteinase screen that protects the lung from proteolytic attack. One hundred and fifty seven patients were recruited from two UK CF centres. The serum concentrations of alpha1-antitrypsin, alpha1-antichymotrypsin and C-reactive protein (CRP) were determined and patients were screened for the common S and Z deficiency alleles of alpha1-antitrypsin and the G-->A mutation in the 3' noncoding region of the alpha1-antitrypsin gene (Taq-I G-->A allele). Alpha1-antitrypsin deficiency phenotypes were detected in 20 (16 MS, 1 S and 3 MZ) out of 147 unrelated tested CF patients and were, surprisingly, associated with significantly better lung function (adjusted mean forced expiratory volume in one second (FEV1) 62.5% of predicted for deficient group and 51.1% pred for normal alleles; p=0.043). The Taq-I G-->A allele was found in 21 out of 150 unrelated patients and had no significant effect on CF lung disease or on levels of alpha1-antitrypsin during the inflammatory response. We show here that, contrary to current thinking, common mutations of alpha1-antitrypsin that are associated with mild to moderate deficiency of the protein predict a subgroup of cystic fibrosis patients with less severe pulmonary disease. Moreover, the Taq-I G-->A allele has no effect on serum levels of alpha1-antitrypsin in the inflammatory response, which suggests that the previously reported association of the Taq-I G-->A allele with chronic obstructive pulmonary disease is not mediated by its effect on the serum level of alpha1-antitrypsin.

Adult↗
PubMed1998

Antithrombin cambridge II (Ala384Ser): clinical, functional and haplotype analysis of 18 families.

Thirty-one individuals from 18 unrelated families with antithrombin deficiency have been identified as having a single point mutation within codon 384 (13268 GCA-->TCA) resulting in an alanine to serine substitution. Six families (11 individuals) were identified by the screening of individuals with thromboembolic disease or with a family history of thromboembolic disease, whilst the remaining 12 families (20 individuals) were identified by screening of asymptomatic blood donors. Four individuals had a history of venous thrombotic disease, a further 2 gave a history of superficial thrombophlebitis but the remaining 25 individuals were asymptomatic. Affected individuals demonstrated normal immunological levels of antithrombin but a decrease in anti-IIa activity in the presence of heparin. Haplotype analysis was used to examine the possibility of a founder effect to explain the high frequency of this non-CpG mutation. 29/31 individuals showed a single common "core" haplotype, the only variation existing in the number of copies of an (ATT)n repeat polymorphism--13, 14, 15 or 17. The results suggest that at most there are four independent origins for this mutation.

Alanine↗
PubMed1997

Mapping sequence specific DNA-protein interactions: a versatile, quantitative method and its application to transcription factor XF1.

We have developed a method for the quantitative, exhaustive sequence specificity determination of DNA-binding proteins. The QuESSD method overcomes the limitations inherent in other published in vitro selection methods, not only defining the consensus sequence, but also quantifying the effect on DNA-protein affinity of replacing each base in the recognition domain with every other base. The features distinguishing this method from other in vitro selection approaches are: (1) instead of synthesizing one target oligonucleotide population containing a long randomized domain, we synthesize several oligonucleotide populations, each randomized at two positions. (2) Instead of carrying out several cycles of selection and amplification, we carry out a single cycle. (3) We have developed data collection and analysis procedures that eliminate artifacts and allow generation of quantitative results. The QuESSD method yields accurate measures of: (a) the selectivity of the protein for each base at each position within the recognition domain (normalized relative selectivity), (b) the contributions of individual sites within the recognition domain to the binding affinity (selectivity variance), (c) the relative binding affinity of any given sequence (global selectivity). We confirmed results by (1) tabulating directly the frequency of appearance of individual species in the pool of protein-bound oligonucleotides by cloning and sequencing individual oligonucleotides, and (2) competition EMSA analysis of oligonucleotides designed on the basis of QuESSD data. We have used this method to map the sequence specificity of the nuclear protein XF1 and to distinguish the sequence specificities of XF1 and the AH receptor complex, both of which bind to XRE1, a xenobiotic responsive element (XRE) located upstream of the CYP1A1 gene. Using data obtained by the QuESSD method, we designed oligonucleotides specific for XF1 or for the AH receptor, and prepared CAT reporter gene constructs carrying these oligonucleotides, or wild-type XRE1, upstream of a minimal promoter. Transfection studies using these constructs indicated that XF1 can function as a weak activator of basal transcription, and can, under some circumstances, compete with the AH receptor for binding to XRE1.

Animals↗
PubMed1997

Resistance to activated protein C and factor V Leiden.

Over the last four years, there has been an explosion of knowledge about APCr and factor V Leiden. However, there remain a considerable number of difficult clinical areas in which there are no clear answers. Undoubtedly, factor V Leiden is commonly found in association with venous thromboembolic disease in whatever manifestation, but equally it has an unusually high frequency in the general population. Only a small proportion of those that carry the mutation develop a thrombosis. It is estimated that only 6% of those that carry the mutation will develop a thrombosis over a 30-year period, whilst for antithrombin, Protein C or Protein S deficiency, this figure is nearer 60%. Particular areas of difficulty remain in relation to the use of the combined OCP and in the management of the asymptomatic carrier of the mutation in pregnancy. Although the scientific basis of APCr and factor V Leiden is well established, its natural history remains relatively poorly understood, probably as a consequence of its relative novelty. Despite the plethora of new data that have appeared, there remains much to be learnt about factor V Leiden and the APCr phenotype.

Adult↗
PubMed1997

Asymptomatic coinheritance of heterozygous plasminogen deficiency and the factor VLeiden mutation.

Deficiency of plasminogen has been postulated by some authors as a possible thrombophilic abnormality, though this remains controversial. We have previously identified a cohort of individuals with plasminogen deficiency from a study to determine plasminogen levels within the general population. All were asymptomatic for thrombosis at initial identification. We followed this cohort over a 5-year period, with no venous thrombotic events recorded, although one patient did suffer a myocardial infarction. One family was identified with asymptomatic coinheritance of both plasminogen deficiency and the factor VLeiden mutation. There was no apparent venous thrombotic risk conferred upon any of our cohort of individuals by inheritance of plasminogen deficiency, and, in addition, the combination of the factor VLeiden mutation with plasminogen deficiency which was observed in three individuals did not result in thrombotic events. However, the cohort is small and we cannot entirely exclude plasminogen deficiency as a possible mild thrombophilic defect.

Adult↗
PubMed1997

Recurrent venous thromboembolic disease and factor XI concentrate in a patient with severe factor XI deficiency, chronic myelomonocytic leukaemia, factor V Leiden and heterozygous plasminogen deficiency.

There are increasing concerns about the potential thrombogenic risks associated with the use of factor XI concentrates. We describe the case of a 49 year-old man with chronic myelomonocytic leukaemia and severe factor XI deficiency (< 1 u/dl), in whom the use of factor XI concentrate appeared to be associated with the development of venous thromboembolic disease. Subsequent investigations revealed the presence of both the factor V Leiden abnormality and heterozygous plasminogen deficiency. This case highlights the risks associated with the use of factor XI concentrates and suggests that these risks may be further increased in patients with an inherited or acquired prothrombotic abnormality or an underlying malignancy. Prothrombotic screening of patients with severe factor XI deficiency may be indicated particularly in younger patients in whom treatment with factor XI concentrates is a possibility.

Factor V↗
PubMed1997

Bovine granulocyte chemotactic protein-2 is secreted by the endometrium in response to interferon-tau (IFN-tau).

Interferon-tau (IFN-tau) is secreted by the bovine conceptus and may regulate synthesis of uterine endometrial cytokines to provide an environment that is conductive to embryo development and implantation. Interferon-tau stimulates secretion of an 8-kDa uterine protein (P8) in the cow. P8 was purified, digested to yield internal peptides, and partially sequenced to determine identity. Two internal peptides had 100% (13-mer) and 92% (12-mer) amino acid sequence identity with bovine granulocyte chemotactic protein-2 (bGCP-2). Bovine GCP-2 is an alpha-chemokine that acts primarily as a potent chemoattractant for granulocyte cells of the immune system. A peptide was synthesized based on a region of bGCP-2 that overlapped with a P8 peptide amino acid sequence, coupled to keyhole limpet hemocyanin, and used to generate high titer polyclonal antiserum in sheep. Western blots revealed that bGCP-2 was not released by endometrium from day 14 nonpregnant cows, but was released in response to 25 nM IFN-tau (p<0.05). Uterine GCP-2 exhibited high affinity to heparin agarose, a characteristic shared by all alpha chemokines. This is the first report describing presence of GCP-2 in the uterine endometrium and regulation by IFN-tau. The regulation of bGCP-2 by IFN-tau may have important implications for cytokine networking in the uterus during pregnancy. Also, the regulation of inflammation and angiogenesis by bGCP-2 working together with other cytokines may be integral to establishing early pregnancy and implantation in the cow.

Amino Acid Sequence↗
PubMed1996

Pinus banksiana has at least seven expressed alcohol dehydrogenase genes in two linked groups.

The alcohol dehydrogenase (Adh) gene family is much more complex in Pinus banksiana than in angio-sperms, with at least seven expressed genes organized as two tightly linked clusters. Intron number and position are highly conserved between P. banksiana and angiosperms. Unlike angiosperm Adh genes, numerous duplications, as large as 217 bp, were observed within the noncoding regions of P. banksiana Adh genes and may be a common feature of conifer genes. A high frequency of duplication over a wide range of scales may contribute to the large genome size of conifers.

Alcohol Dehydrogenase↗
PubMed1996

Molecular genetics of human antithrombin deficiency.

Human antithrombin is the major plasma inhibitor of thrombin both in the presence and absence of heparin. Its physiological importance is emphasised by the recurrent thromboses that individuals with a deficient or functionally abnormal protein are prone to develop. Such deficiencies are estimated to affect as many as 1:630 of the general population and between 3% and 5% of patients with thrombotic disease. The gene for antithrombin (AT3) has been cloned and shown to map to the long arm of chromosome 1 at 1q23-25. The gene consists of seven exons and six introns and spans 13,477bp of DNA. Advances in molecular genetic techniques have facilitated identification of the underlying DNA mutation(s) in > 80 families with antithrombin deficiency. Such work has proved invaluable in structure-function studies and in helping to provide informed genetic counselling to "at-risk" individuals based upon the natural history of similar variants.

Antithrombins↗
PubMed1996

Low thrombosis rate seen in blood donors and their relatives with inherited deficiencies of antithrombin and protein C: correlation with type of defect, family history, and absence of the factor V Leiden mutation.

We have previously identified a group of blood donors with inherited deficiencies of either antithrombin (AT) or protein C who appear to have a relatively low thrombosis rate. In the 5 years that have elapsed since initial identification of these individuals, resistance to activated protein C (APC resistance), which is associated with the factor V Leiden gene mutation, has emerged as an important and highly prevalent inherited thrombophilic risk factor. We have followed 28 donors/relatives with deficiency of AT (median age 48 years, range 16-77) and 23 with deficiency of protein C (median age 44 years, range 15-79) over a period of 5 years. During the study period only one individual, who was previously symptomatic, has suffered a thrombotic event which occurred spontaneously whilst on warfarin. We have now excluded coinheritance of APC resistance due to the factor V Leiden mutation in our cohort. Our findings demonstrate that individuals with single inherited thrombophilic defects are not uncommon and are frequently asymptomatic. The absence of the factor V Leiden mutation may in part explain the low thrombosis rate observed, and lends support to the hypothesis that multiple thrombophilic defects may be necessary for the development of thrombosis.

Adolescent↗
PubMed1996

Type I antithrombin deficiency: five novel mutations associated with thrombosis.

The genetic basis of Type I antithrombin deficiency has been investigated in six unrelated kindred with positive histories of thrombosis using a PCR amplification/direct sequencing approach. Four frameshift mutations, all introducing premature translation termination codons were identified. Thus, deletions, of a C at nucleotide position 2599 or 2600, a G at position 2601-2602 and a CT dinucleotide at position 7428-7429 were detected in three kindred and confirmed by restriction enzyme analysis. The identical insertion, of a T at nucleotide 2770, was observed in two apparently unrelated families. This finding may have been due to a founder effect since antithrombin gene polymorphism analysis showed all affected individuals to share a common haplotype. An in frame deletion of 6 bp at nucleotide position 2690-2696 causing the removal of codons 76 and 77 encoding Ile 76 and Phe 77 was also detected indicating that these amino acids are essential for stability of the mature antithrombin.

Adult↗
PubMed1995

Two antithrombin mutations in a compound heterozygote: Met20Thr and Tyr166Cys.

The molecular basis for a family with Type I antithrombin deficiency has been established. Amplification and sequencing of the antithrombin gene identified two mutations: Met20Thr (2523T-->C) within exon 2 and Tyr166Cys (5493A-->G) within exon 3a. Further analysis indicated that the propositus was a compound heterozygote but in addition provided evidence for phase disruption during the amplification and/or cloning procedure. The Met20Thr mutation appears to be a neutral mutation with no functional consequences. In contrast, the Tyr166Cys mutation is associated with a Type I phenotype.

Antithrombin III↗