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Biomedical subjects

D Gaffney

Publications and source records attributed to D Gaffney.

At least 37 records · Page 2Linked to original sources
PubMed1998

Influence of polymorphism Q3405E and mutation A3371V in the apolipoprotein B gene on LDL receptor binding.

Familial defective apolipoprotein B (FDB) is due to mutations in the apolipoprotein B (apo B) gene at codon 3500 or 3531 that affect low density lipoprotein (LDL) receptor binding. From sequence analysis the putative receptor binding site was believed originally to be upstream from this at residues 3147-3157 and 3357-3367. Using denaturing gradient gel electrophoresis, mutations were sought in codons 3350-3466. This includes the important positively charged residues 3357-3367. DNA from 928 hyperlipidaemic individuals was studied and two hitherto unknown DNA changes were discovered, one of which resulted in an altered amino acid in the apo B. A known polymorphism Q3405E was also detected at a carrier frequency of 1.4%. Using growth of U937 cells as a measure of binding affinity of LDL to its receptor the newly discovered mutant A3371V permitted the same growth as LDL from normolipidaemic individuals of the U937 cells, however, the LDL from Q3405E individuals permitted only 77% of the normal growth (P=0.009).

Adult↗
PubMed1998

Identification of a common low density lipoprotein receptor mutation (C163Y) in the west of Scotland.

Familial hypercholesterolaemia (FH) is an autosomal codominant disorder characterised by high levels of LDL cholesterol and a high incidence of coronary artery disease. Our aims were to track the low density lipoprotein receptor (LDLR) gene in individual families with phenotypic FH and to identify and characterise any mutations of the LDLR gene that may be common in the west of Scotland FH population using single strand conformational polymorphism analysis (SSCP). Patient samples consisted of 80 heterozygous probands with FH, 200 subjects who were related to the probands, and a further 50 normal, unrelated control subjects. Tracking of the LDLR gene was accomplished by amplification of a 19 allele tetranucleotide microsatellite that is tightly linked to the LDLR gene locus. Primers specific for exon 4 of the LDLR gene were used to amplify genomic DNA and used for SSCP analysis. Any PCR products with different migration patterns as assessed by SSCP were then sequenced directly. In addition to identifying probands with a common mutation, family members were screened using a forced restriction site assay and analysed using microplate array diagonal gel electrophoresis (MADGE). Microsatellite D19S394 analysis was informative in 20 of 23 families studied. In these families there was no inconsistency with segregation of the FH phenotype with the LDLR locus. Of the FH probands, 15/80 had a mutant allele as assessed by SSCP using three pairs of primers covering the whole of exon 4 of the LDLR gene. Direct DNA sequencing showed that 7/15 of the probands had a C163Y mutation. Using a PCR induced restriction site assay for the enzyme RsaI and MADGE, it was determined that the C163Y mutation cosegregated with the FH phenotype in family members of the FH probands. This mutant allele was not present in any of the control subjects. Microsatellite analysis has proven useful in tracking the LDLR gene and could be used in conjunction with LDL cholesterol levels to diagnose FH, especially in children and young adults where phenotypic diagnosis can be difficult.

Adult↗
PubMed1998

Hematologic and serum biochemical variables and plasma corticotropin concentration in healthy aged horses.

OBJECTIVES: To compare hematologic and serum biochemical variables and plasma ACTH concentration between healthy horses 5 to 12 years old and those more than 20 years old. ANIMALS: 30 healthy horses 5 to 12 years old and 30 healthy horses more than 20 years old. PROCEDURES: Venous blood was collected from all horses, and CBC and serum biochemical analysis were performed for each horse. Plasma ACTH concentration was determined by radioimmunoassay. Student's paired t-test or the Mann-Whitney rank sum test was used to compare values between control and aged horse groups. RESULTS: Compared with values for control horses, aged horses had significantly higher erythrocyte mean cell volume and mean cell hemoglobin. Aged horses also had significantly decreased total lymphocyte count. Five aged horses had lymphocyte count that was lower than the low reference limit as established for horses in our laboratory. Differences between control and aged horses for serum biochemical or plasma ACTH values were not significant. CONCLUSION: Compared with younger adult horses, those more than 20 years old have some hematologic differences, but there is no apparent effect of aging on baseline plasma ACTH concentration. CLINICAL RELEVANCE: It is important to establish age-matched control values for optimal interpretation of clinicopathologic variables.

Adrenocorticotropic Hormone↗
PubMed1997

Acute services. Time to strip the beds?

The health authority and trust proposals for Birmingham's health services, currently the subject of consultation, are radical, untested and uncosted. They assume that once emergency assessment and ambulatory care centres are operational, under half the current caseload will need inpatient stays. University Hospital Birmingham trust's proposal for a new hospital built and operated by the private sector assumes no growth in activity and a 17 per cent reduction in the present bed complement, at a time when emergency admissions in Birmingham are increasing by 5 per cent a year. Analysis of the proposals suggests they will destabilise an already precarious acute service in Birmingham.

Ambulatory Care↗
PubMed1995

Use of a stable copper isotope (65Cu) in the differential diagnosis of Wilson's disease.

1. 65Cu/63Cu stable-isotope ratios have been measured in blood serum after oral administration of the stable isotope 65Cu. The incorporation of the isotope into the plasma protein pool was followed at various times for up to 3 days. The resulting patterns of enrichment in healthy control subjects, in Wilson's disease patients and in heterozygotes for the Wilson's disease gene, were similar in appearance to those found by others using copper radioactive isotopes. After an initially high enrichment at 2 h after dosage, the Wilson's disease cases, in contrast to the control subjects, did not show a secondary rise in isotope enrichment of the plasma pool after 72 h, demonstrating a failure to incorporate copper into caeruloplasmin. The Wilson's disease heterozygotes had variable degrees of impairment of isotope incorporation, not always distinguished from those of control subjects. 2. The stability of the isotope also permits the copper tracer to be followed for a longer period. Ten healthy subjects were studied for over 40 days, allowing the biological half-time of an oral dose of copper to be determined (median 18.5 days, 95% confidence interval 14-26 days). Known heterozygotes for the Wilson's disease gene were found to have a significantly increased biological half-time for removal of copper from the plasma pool (median 43 days, 95% confidence interval 32-77 days). 3. The incorporation of 65 Cu in patients with diseases of the liver (other than Wilson's disease) was found to be similar to that in control subjects, aiding differential diagnosis.

Adolescent↗
PubMed1995

Independent mutations at codon 3500 of the apolipoprotein B gene are associated with hyperlipidemia.

The apoB arginine-to glutamine change at codon 3500 has become established as a cause of failure of binding of the LDL particle to its receptor and the consequent hypercholesterolemia of familial defective apoB 100. A search for further similar mutations was undertaken by systematic screening of a candidate region of the apoB gene from individuals with hypercholesterolemia. Polymerase chain reaction and denaturing gradient gel electrophoresis were used. We describe two families in which a different mutation in the codon 3500 causes an arginine-to-tryptophan substitution. Most adults in these families who have this mutation have hypercholesterolemia. LDL derived from all who have inherited the mutation is dysfunctional in that it allows only poor growth of an LDL cholesterol-dependent cell line. We conclude that this arginine 3500 is essential to the function of apoB and that its loss and replacement by glutamine or tryptophan is responsible for the hypercholesterolemia of familial defective apoB 100.

Adolescent↗
PubMed1994

Children's lives or garden aesthetics? A case study in public health advocacy.

Following a decade of accumulating clinical reports on child drowning in domestic swimming pools, paediatricians began advocating legislation that would require all pools to be 'isolation' fenced. In 1990, the New South Wales Government introduced and then repeated such legislation following intense lobbying and media advocacy from a group of pool owners. This paper reviews the ways in which isolation fence advocates and opponents framed their public arguments. Five main areas of competing public discourse are identified: why pool drownings occur; the effects of fencing; expert views and community support; the role of the state in prevention; and personalised references to the value systems of those involved in the debate. Two factors seem likely to have contributed most to the overthrow of the legislation: fence opponents inhabiting the same noninterventionist ideological frame of reference as the government; and fence advocates' refusal to compromise on retrospective fencing seems likely to have inspired a commitment in opposition which would have been absent if an incrementalist, prospective fencing policy had been adopted.

Child, Preschool↗
PubMed1994

A PCR based method to determine the Kalow allele of the cholinesterase gene: the E1k allele frequency and its significance in the normal population.

The Kalow allele for cholinesterase is a quantitative variant of the usual gene and has been shown to result from a single base pair change in the DNA. A new method based on the polymerase chain reaction to distinguish Kalow alleles of the cholinesterase gene was developed. Using the amplification refractory mutagenesis system, two different reactions distinguished the presence of a guanine (normal E1u allele) from that of an adenine (Kalow E1k allele) at nucleotide 1615 within the coding sequences of the gene. The frequency of the Kalow allele in our sample of 51 persons was determined to be 20%. The mean total cholinesterase activity in heterozygotes was 90% of that in persons who typed as E1uE1u homozygotes. Two E1kE1k homozygotes were identified and their cholinesterase activities were the two lowest measured.

Adult↗
PubMed1994

Regulation of plasma HDL cholesterol and subfraction distribution by genetic and environmental factors. Associations between the TaqI B RFLP in the CETP gene and smoking and obesity.

This study investigated in a healthy population (n = 220) the association of the TaqI B restriction fragment length polymorphism (RFLP) in the cholesteryl ester transfer protein (CETP) gene with plasma high-density lipoprotein (HDL) cholesterol concentration and subfraction distribution. A raised HDL cholesterol level was found in B2B2 homozygotes (B2 cutting site absent) and was associated specifically with a 45% increase in HDL2 compared with B1B1 homozygotes (B1B1, 77 +/- 39 mg/100 mL, mean +/- SD; B2B2, 112 +/- 59 mg/100 mL; P < 0.01). Total plasma, very-low-density lipoprotein, and HDL triglyceride levels did not differ among the genotype groups, nor did plasma apolipoprotein AI levels (B1B1, 1.45 +/- 0.35 mg/mL, mean +/- SD; B2B2, 1.56 +/- 0.33 mg/mL). Thus, the genetic variation appeared to be independent of metabolic factors that are known to regulate HDL levels. Plasma CETP exchange activity was unlikely to be the cause of the association, since it did not differ between genotype groups and was not correlated with HDL2 concentration. Multivariate analysis demonstrated that the TaqI B polymorphism had an effect on HDL cholesterol and HDL2 that was independent of age, sex, body mass index, oral contraceptive use, exercise, alcohol consumption, and plasma triglycerides. In smokers, the presence of the B2B2 genotype did not result in increased HDL cholesterol or HDL2, whereas in obese subjects, the difference between B1B1 and B2B2 individuals was diminished. We conclude that the TaqI B RFLP is associated with a quantitatively significant effect on plasma HDL2 levels that is independent of plasma triglycerides and interacts with lifestyle factors.

Adult↗
PubMed1994

Human major histocompatibility complex contains several leukemia susceptibility genes.

In mice, homozygosity for the Mhc haplotype H-2k is associated with increased susceptibility to spontaneous and virus-induced leukemia, lymphoma and other neoplasms in the predisposed host. The influence of the Mhc on malignant development in these models is to shorten the latency after virus inoculation. Here, we present evidence that a similar phenomenon results in early-onset of human leukemia. A molecular analysis of the MHC in 112 CML patients showed that those who developed the disease when aged less than 35 years (early-onset group) had higher homozygosity rates for the DOA1, HSP70 and C4 alleles of the DR53 group of ancestral haplotypes, for a subtype of HLA-A3, and a higher allele frequency of BfFb compared to the late-onset group. The oldest patient (n = 13) homozygous for DR53 was 52-years-old (p = 0.004), and all HLA-A3 homozygous patients (n = 4) were in the early-onset group (p = 0.01). The relative risk for early-onset CML yielded by HLA-A3 homozygosity was 17.6. The well-known serological HLA-Cw4 association was not confirmed at the DNA level and thought to be due to linkage disequilibrium with BfFb. The factor B association was sex-limited. The DR52 group haplotypes appeared to be protective. The HLA-identical sibling frequency was increased only in the early-onset group (p < 0.01). Our findings agree with the concept of an MHC influence on the development of malignancies. The similarity in the location of the susceptibility loci and the serological cross-reaction between H-2Ek and DR53 raise the possibility that the mouse and human MHC share the same leukemia susceptibility genes.

Acute Disease↗
PubMed1993

The ins/del polymorphism in the signal sequence of apolipoprotein B has no effect on lipid parameters.

The 'ins/del' polymorphism in the signal sequence of apolipoprotein B alters the hydrophobicity of the signal sequence and therefore would be expected to affect the rate of production of apolipoprotein B (apo B) and the plasma concentrations of lipoproteins containing this apolipoprotein. We sought evidence for an association with plasma lipid levels and this polymorphism in two studies, one using a normal randomly selected population (N = 188) and another using a mildly hypercholesterolaemic group of men aged 45-64 (N = 360). The frequency of the rarer, 'del' allele, was the same in both groups. Likewise no differences in serum cholesterol, serum triglycerides, very low density lipoprotein, low density lipoprotein or high density lipoprotein were seen comparing homozygotes for the signal sequence allele within either group.

Apolipoproteins B↗
PubMed1993

Frequency of the XbaI, EcoRI, PvuII and MspI polymorphisms of the apolipoprotein B gene in relation to hypercholesterolaemia in the general population.

In this study the frequencies of the genotypes of four restriction fragment length polymorphisms in the apolipoprotein B gene (XbaI, EcoRI, PvuII and MspI) are compared between groups of normolipidaemic and diet resistant hypercholesterolaemic individuals as possible markers for the influence of this gene on plasma cholesterol levels. In the first part of the study genotypes of all four markers were determined in 92 normolipidaemic (mean cholesterol 5.6 + 0.8 mmol/l) and 79 diet resistant hypercholesterolaemic (mean cholesterol 7.8 + 0.7 mmol/l) individuals seen in a local health centre screening programme for coronary heart disease risk factors. No significant difference was seen in the frequencies of the EcoRI and PvuII genotypes between the two groups. There was significant enrichment of both the XbaI X2 (presence of cutting site) allelic frequency and of the MspI M1M2 (M2 absence of cutting site, rarer allele) genotype frequency in the hypercholesterolaemic group. In the second part of the study an independent larger group of individuals, seen in a multicentre screening programme across the city of Glasgow, were genotyped for the two potentially significant polymorphic sites (XbaI and MspI). From this second screening programme 188 age matched normolipidaemic males (mean cholesterol 5.0 +/- 0.8 mmol/l) were compared with 186 males who were still hypercholesterolaemic (mean 8.2 +/- 0.6 mmol/l) after three months dietary intervention. The hypercholesterolaemic individuals in this second study did not show a significant enrichment of the XbaI X2 allele but again showed a highly significant enrichment of the MspI M1M2 genotype. This genetic effect may relate directly to the charge change from arginine to glutamine at amino acid 3611 caused by the MspI mutation or to an as yet unknown functionally significant mutation in linkage disequilibrium with this site.

Adult↗
PubMed1993

Smoking and plasma lipoproteins in man: effects on low density lipoprotein cholesterol levels and high density lipoprotein subfraction distribution.

In a survey of a healthy population (n = 197), LDL cholesterol, plasma triglycerides and VLDL triglycerides were found to be substantially increased and plasma HDL cholesterol decreased in smokers. The lipid-associated atherogenic risk in smokers as assessed by the LDL/HDL ratio was significantly higher [2.89 (SD 1.18, n = 63)] than in non-smokers [2.38 (SD 0.98, n = 86) P < 0.01]. The lower HDL level found in smokers was explained by a lower HDL-2 subfraction as determined by analytical ultracentrifugation. HDL 2b, 2a and 3a, measured by gradient gel electrophoresis, were all lower in the smokers but this was only significant for HDL 2a. Smoking had no effect on Lp(a) levels. HDL cholesterol and HDL-2 were strongly negatively correlated whereas LDL cholesterol and LDL/HDL ratio were strongly positively correlated with the plasma triglyceride concentration. There was a small but significant reduction in plasma CETP activity [non-smokers 49% t/microliter (SD 17, n = 90), smokers 43% t/microliter (SD 17, n = 66) P < 0.05] but CETP activity was not correlated with any measure of HDL in this population. Smoking was found to be an important independent contributor to the variation in plasma triglyceride, HDL, HDL-2 and LDL/HDL ratio. After correcting for sex, age, BMI, alcohol consumption, oral contraceptive use and plasma triglycerides smoking was still found to be significantly associated with HDL and the LDL/HDL ratio. Upon adjustment for covariant factors the mean differences between smokers and non-smokers for HDL cholesterol, HDL-2 and LDL/HDL were 0.15 mM, 16 mg dl-1 and 0.39 respectively. There appeared to be important sex differences in the influence of smoking on plasma lipoproteins. In women the main impact of smoking was on triglyceride levels and they in turn affected LDL and HDL. In contrast, in men, smoking had little impact on triglycerides and affected HDL more directly. We conclude that smoking cigarettes has an important effect on plasma lipoprotein metabolism through multiple mechanisms.

Adult↗