PubMed Health⌕ Search

Biomedical subjects

A E Thomas

Publications and source records attributed to A E Thomas.

At least 19 recordsLinked to original sources
PubMed2004

The bleeding child; is it NAI?

As a paediatric haematologist, the question of whether a child has been abused or whether they might have a bleeding diathesis is a question that I am regularly asked. When I first became a consultant, I would often find that not enough information was available; for example, incomplete histories had been taken or investigations were incomplete and difficult to interpret. This inevitably led to delays in confirming the cause of the bleeding and meant that if parents or carers contested a diagnosis of abuse, excluding a bleeding disorder was extremely difficult. I was also aware that carers of several of my patients with haemophilia or other bleeding disorders had initially been under suspicion of abuse, most usually at the time of the first few presentations. By highlighting important questions in history taking, having a specific haematological screen for children being investigated for bleeding in the context of non-accidental injury, and encouraging discussion of abnormal results with a haematologist, these difficulties can, for the most part, be avoided.

Child↗
PubMed2000

Haemophilia care in central Scotland 1980-94. I. Demographic characteristics, hospital admissions and causes of death.

To estimate the resources required to manage patients with haemophilia in Scotland, we studied the demographic features, hospital admissions and causes of deaths for individuals with haemophilia A and B and von Willebrand disease, treated with blood products, during the period 1980-94 living in central Scotland. Data were obtained from 413 adults and children (93% ascertainment). The age distribution in 1980 revealed a paucity of individuals over 60 years but the number in this age group increased over the study period. Of those with haemophilia A and B, 63 and two respectively, became HIV positive. Hospital admissions rose from 103 to 168 per annum; the number of annual bed days utilized also increased, but there was marked annual fluctuation (790-1832). The rate of admission was greater for those with severe haemophilia A and this increased during the 15-year period mainly due to the clinical consequences of human immunodeficiency virus (HIV) and hepatitis C virus (HCV). The admission rate for haemophilia B was significantly lower than that for haemophilia A, and was similar for all degrees of severity of the disorder. Throughout the 15-year period the incidence of admissions for acute bleeds was constant, as was the average duration in hospital. For those with a factor VIII inhibitor, the rate of admission was about double the rate of those without an inhibitor, although the duration of hospital stay was similar for both groups. There were 61 deaths; the death rate increased during the study period principally due to HIV and HCV, and 12 patients died from haemorrhage. We conclude that: (i) the life expectancy for haemophiliacs in Scotland was generally increasing, although HIV and HCV caused increasing mortality and morbidity (as shown by the increase in hospital admissions); (ii) hospital bed usage for the treatment of acute bleeds continued to be required, but fluctuated greatly; and (iii) the clinical impression that haemophilia B is less clinically severe than haemophilia A is confirmed by objective data. The planning implications for haemophilia care in Scotland and similar countries are discussed.

Adolescent↗
PubMed2000

The value of book distribution in a clinic-based literacy intervention program.

The purpose of this study was to determine whether anticipatory guidance at well-child visits (WCV) that included early literacy development and the provision of books by the examining physician changed family literacy practices. It was conducted in an inner-city pediatric clinic that serves as the continuity practice site for pediatric and pediatric/internal medicine residents. There were 352 children (181 treatment: 171 control), aged 2 to 24 months, enrolled in this prospective, controlled study. The health care providers underwent training on literacy and on how to incorporate this information during WCV. Anticipatory guidance on safety, development, and early literacy was given to all parents. Additionally, the treatment group received an age-appropriate book at each WCV. There were 1,263 visits made (686 treatment, 577 control). Questionnaires were completed by parents on physician helpfulness and by physicians on parental receptiveness. Parental ratings on physician helpfulness were higher in the treatment group than in the control group (p<0.05). Physician's rating of parental receptiveness was also higher in the treatment group than in the control group (p<0.05). Two years after enrollment, mother-child pairs who received guidance and a book were two times more likely to report enjoyment in reading together than the controls who received guidance but no book. We conclude that anticipatory guidance that included early literacy development and distribution of books at WCV resulted in increased family literacy orientation, parental receptiveness, and perception of physician helpfulness.

Child Guidance↗
PubMed1999

Analysis of thiopurine methyltransferase variant alleles in childhood acute lymphoblastic leukaemia.

The role of 6-mercaptopurine (6MP) in the treatment of childhood acute lymphoblastic leukaemia (ALL) is well established. However, the efficacy of 6MP is significantly influenced by inactivation by the polymorphic enzyme thiopurine methyltransferase (TPMT). In the general population 89-94% have high TPMT activity, 6-11% have intermediate activity, and approximately 0.3% have low activity. Individuals with low-activity experience severe or fatal toxicity with standard 6MP doses. Prospective identification of this group of patients might prevent this problem. Recent identification of the molecular basis for low TPMT activity enabled rapid assessment of altered 6MP metabolism by PCR methods. This study evaluated the frequency of mutant TPMT alleles in 147 children with ALL. One patient was homozygous mutant (0.7%), and 16 patients were heterozygous for variant TPMT alleles (10.9%). The majority of mutant alleles were TPMT*3A. Both the allele frequency and the pattern of TPMT mutations were similar to that observed in an adult British population. The number of weeks when 6MP therapy was administered at full dose was determined in patients on MRC UKALL X and XI. The 94 patients spent a median 11% of the maintenance period receiving no therapy as a result of haematological toxicity. There was no significant difference in the number of weeks when no therapy could be administered among patients with a wild-type or heterozygous genotype. However, the one patient with a homozygous mutant genotype had severe haematological toxicity and no therapy could be administered for 53% of the maintenance period. This study demonstrates that 11.6% of the children had variant TPMT alleles. Prospective identification of TPMT genotype may be a promising tool for decreasing excessive haematological toxicity in individuals with low activity.

Adult↗
PubMed1997

Neurogenic chronic idiopathic intestinal pseudo-obstruction, patent ductus arteriosus, and thrombocytopenia segregating as an X linked recessive disorder.

We present a family with three affected males in two generations with congenital neurogenic chronic idiopathic intestinal pseudo-obstruction (CIIP), patent ductus arteriosus, and large platelet thrombocytopenia apparently segregating as an X linked recessive disorder. The pattern of segregation of DNA markers within the family is consistent with linkage to the previously described neurogenic CIIP (CIIPX) locus at Xq28. This combination may represent a new contiguous gene disorder and appears to have a good prognosis with supportive therapy.

Abnormalities, Multiple↗
PubMed1996

Association of genetic variation at the beta-fibrinogen gene locus and plasma fibrinogen levels; interaction between allele frequency of the G/A-455 polymorphism, age and smoking.

The beta-fibrinogen G/A-455 polymorphism genotype along with plasma fibrinogen levels was determined in 482 healthy middle-aged men, of whom 231 were smokers. Smokers had the highest plasma fibrinogen levels (2.92 g/l), ex-smokers the next (2.73 g/l), and never-smokers the lowest levels (2.66 g/l, P < 0.001). Those with one or two A-455 alleles had significantly higher plasma fibrinogen levels in never-smokers and ex-smokers (8.2% and 9.0%, respectively, P < 0.05), and the effect was larger in younger men (45 < 55 years, 11.6%, P = 0.002) than older men (> 65 years, 4.5%, NS), and was not significant in smokers (2.4%, P > 0.05). Allele frequencies were calculated and compared across age groups and between smokers and non-smokers. The difference in frequency of the A-455 allele between smokers and non-smokers varied significantly with age (P < 0.01), with the frequency of the A-455 allele being significantly lower in smokers than in non-smokers in subjects aged > 65 years (P < 0.05), but not in younger men. This demonstrates an interaction between age, smoking and allele frequency of the G/A-455 polymorphism in this population-based sample.

Age Factors↗
PubMed1995

The association of combined alpha and beta fibrinogen genotype on plasma fibrinogen levels in smokers and non-smokers.

OBJECTIVE: To determine in healthy men: (1) whether an extended genotype of the fibrinogen gene cluster using the G/A-455 and the BclI polymorphism of the beta fibrinogen gene and TaqI of the alpha fibrinogen gene explains a significantly larger proportion of variance in plasma fibrinogen levels in either smokers or non-smokers than a single polymorphism (G/A-455); (2) whether there is any evidence for genotype-smoking interaction in the determination of fibrinogen levels. DESIGN: A cross sectional study of healthy, white men recruited at the screening for entry into the Thrombosis Prevention Trial. SETTING: The subjects were drawn from four general practices in the United Kingdom. RESULTS: The frequency of the rare alleles in the sample was 0.19 for the G/A-455 polymorphism (A-455), 0.15 for BclI (B+), and 0.27 for TaqI (T+) alleles. BMI and age made significant contributions to the variance in plasma fibrinogen levels only in non-smokers of 5.4% and 2.3% respectively and, in the group as a whole, smoking accounted for 6.6% of the variance. In the non-smokers, of the individual polymorphisms only the G/A-455 showed a significant association with plasma fibrinogen levels (p = 0.03). The mean fibrinogen in non-smokers homozygous for the G-455 allele was 2.54 g/l v 2.85 g/l in those homozygous for the A-455 allele, with the polymorphism explaining 3.6% of the variance in plasma fibrinogen levels in this group. On investigation of the association of fibrinogen levels with combined genotypes, the most significant effect was seen with the combination of the G/A-455 and TaqI polymorphisms, with those with no "fibrinogen raising alleles" having a mean fibrinogen of 2.57 g/l v 3.10 g/l for those with four "fibrinogen raising alleles" (p = 0.0036), and this combination explained 8.9% of the variance in plasma fibrinogen levels (p < 0.005). Although the contribution to variance was greater with the G/A-455/TaqI combination than the G/A-455 polymorphism alone (8.9% v 3.6%), this did not reach significance (p = 0.09). By contrast, in the smoking group, the only significant contribution to the difference in plasma fibrinogen levels was the G/A-455 genotype alone which, after adjustment for BMI and age, contributed 3.8% to the variance (p < 0.05). No interaction was shown between smoking and genotype. CONCLUSION: These data suggest that in non-smokers an extended genotype using the G/A-455 beta fibrinogen gene polymorphism and the TaqI alpha fibrinogen gene polymorphism explains a larger proportion of the variance in plasma fibrinogen levels than any one polymorphism alone, but that smoking has an overriding effect so that other variables such as age and BMI make little additional contribution.

Alleles↗
PubMed1995

Gender-related association between beta-fibrinogen genotype and plasma fibrinogen levels and linkage disequilibrium at the fibrinogen locus in Greenland Inuit.

Elevated plasma fibrinogen levels represent an increased risk for cardiovascular disease, but the mechanism explaining this association is still not clear. Genetic differences may play a role, because it has been shown that individuals who carry the rare alleles of polymorphisms in the genes for the B beta-chain (Bcl I and G/A-455) and the A alpha-chain (Taq I) of fibrinogen have higher plasma fibrinogen levels and that patients with peripheral arterial disease have a higher frequency of the rare allele of the Bcl I polymorphism than do healthy control subjects. We studied the Greenland Inuit, a population with a low incidence of ischemic heart disease; polymorphisms of the fibrinogen gene; and their association with plasma fibrinogen level. The group studied had a small age range (30 to 34 years), 97% were smokers, 62 were men, and 71 were women. We observed that in the Inuit, frequencies of the rare alleles of the beta gene and of the common alleles of the alpha gene polymorphisms were lower than those published for other populations (all Caucasian). Accordingly, in the Inuit, these distribution patterns give a higher frequency of alleles that are associated with lower plasma fibrinogen levels. We further observed comparable linkage disequilibrium between alpha and beta gene polymorphisms in Caucasian populations. In Inuit men the rare allele of the Bcl I and G/A-455 fibrinogen polymorphisms was associated with plasma fibrinogen level comparable with the association described in Caucasian populations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Enhanced platelet reactivity and hypercoagulability in the steady state of sickle cell anaemia.

A prospective controlled study was undertaken to investigate the haemostatic and coagulation status of 18 adult subjects in the steady state of sickle cell anaemia (SCA), using a relatively new in vitro technique. Shear induced haemostasis, whole blood dynamic coagulation, and spontaneous thrombolysis were measured using nonanticoagulated blood. As expected, the haemoglobin levels were significantly lower and platelet counts significantly higher in subjects with SCA compared with controls. Haemostasis and coagulation were significantly enhanced in SCA. No correlation was found between the raised platelet count and enhanced haemostasis or the reduced haemoglobin and hypercoagulation, respectively. Hyperactivity of the haemostatic system may have a pathogenic role in vaso-occlusive microthrombotic events and in the leg ulcers, both of which occur frequently in SCA.

Adolescent↗
PubMed1991

Variation in the promoter region of the beta fibrinogen gene is associated with plasma fibrinogen levels in smokers and non-smokers.

We investigated the association between fibrinogen levels and a HaeIII restriction fragment length polymorphism located at -453 bp from the start of transcription of the beta fibrinogen gene. 292 healthy men aged 45 to 69 years, recruited from general practices throughout Britain, were studied. None had a history of ischaemic heart disease. 41.1% (120) were smokers and fibrinogen levels were higher in this group. The frequency of the non-cutting allele (designated H2) was 0.19 and was the same in smokers and non-smokers. The H2 allele was associated with elevated levels of fibrinogen in both smokers and non-smokers and the effect of genotype was similar in both groups. After smoking, HaeIII genotype was the strongest predictor of fibrinogen levels and explained 3.1% of the variance in fibrinogen levels. These results confirm earlier studies that variation at the fibrinogen locus contributes to the between-individual differences in plasma fibrinogen level.

Base Sequence↗
PubMed1989

Homozygous protein C deficiency with delayed onset of symptoms at 7 to 10 months.

We report an inbred family with two cases of homozygous protein C deficiency and review 11 other such cases. Both patients presented in the second half of their first year of life with recurrent rapidly disappearing ecchymotic skin lesions, disseminated intravascular coagulation, and venous thrombosis. Successful treatment has been achieved by frequent infusions of plasma or prothrombin complex then maintained with Warfarin. Homozygous recessive protein C deficiency usually presents in the neonatal period with purpura fulminans. Two cases have been described elsewhere which presented in the second decade of life with milder symptoms. The present cases appear to be intermediate in time of presentation and severity of symptoms. We also review the distinction that is now evident between recessive and dominant protein C deficiency.

Consanguinity↗