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Biomedical subjects

P M Dodson

Publications and source records attributed to P M Dodson.

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

Linkage disequilibrium between the human leukocyte antigen class II region of the major histocompatibility complex and Graves' disease: replication using a population case control and family-based study.

Early case control studies found association of the DRB1 allele, DR3, with Graves' disease (GD). Recent reports, claim the DQA1 allele, DQA1*0501, to be the primary susceptibility determinant within the human leukocyte antigen (HLA) class II region. We typed 228 GD patients, 364 controls, and 98 families (parents, GD, and unaffected sibling) at the DRB1, DQB1, and DQA1 loci. The case control study showed an increased frequency in GD, compared to controls, of DRB1*0304 (47% vs. 24%; pc < 1.4 x 10(-5)), DQB1*02 (58% vs. 46%; pc < 0.035), DQB1*0301/4 (42% vs. 28%; pc < 3.5 x 10(-3)) and DQA1*0501 (67%, vs. 39%; pc < 7 x 10(-6)). The DRB1*0304-DQB1*02-DQA1*0501 haplotype was increased in GD (47%) vs. controls (24%; pc < 1.8 x 10(-5); odds ratio = 2.72). No independent association of these alleles was observed. Preferential transmission of DRB1*0304-DQB1*02-DQA1*0501 from parents heterozygous for the haplotype to GD siblings (72%) was seen in the families (chi2 = 11.95; 1 d.f.; P = 0.0005). Lack of preferential transmission to unaffected siblings (53%; chi2 = 0.19; 1 d.f.; P = NS) excluded segregation distortion. These results show that linkage disequilibrium between GD and the HLA class II region is due to the extended haplotype DRB1*0304-DQB1*02-DQA1*0501.

Alleles↗
PubMed1997

Sex hormone preparations and retinal vein occlusion.

Retinal vein occlusion (RVO) is most commonly seen in middle-aged or older patients and is associated with underlying cardiovascular risk factors. It is much less common in younger patients. Use of the oral contraceptive pill (OCP) is known to be a risk factor for cardiovascular and cerebrovascular disease. There have previously been a few isolated case reports of patients sustaining an RVO whilst taking the OCP. The aim of this study was to investigate patients sustaining an RVO whilst taking the OCP or hormone replacement therapy (HRT). From a large series of 588 patients, we found 11 with an RVO associated with sex hormone preparations. Of these, 6 had taken the OCP and 5 were HRT users. From this large group there were only 9 female patients aged under 35 years who sustained an RVO. Of these, 6 were associated with use of the OCP. All patients were investigated for recognised medical risk factors for RVO. None of these factors were identified in the patients who had used the OCP. Of the patients taking HRT, 4 of the 5 had other potential risk factors. From our large series, the prevalence of RVO in female patients under 35 years taking the OCP was 66%. There is a 30% uptake of the OCP in the general population. These data support the view that RVO is a contraindication to the use of the OCP. Additionally, it would appear (albeit from limited data) that patients who sustain RVO may continue with their HRT, as HRT is not a major single risk factor for RVO.

Adult↗
PubMed1997

Diabetic eye disease: a natural history study.

In previous studies on diabetic retinopathy it has not been possible to relate risk factors to reduced vision because of the influence of vision-preserving treatment. Demographic data, cardiovascular risk factors and ocular features from the diabetic population of the Seychelles are described. Diabetic retinopathy in this population had not been modified by laser treatment. The population described consists of entirely type 2, maturity onset diabetics. Using a multivariate logistic regression model, the risk factors were deduced for three outcome variables: (1) reduced vision, defined as 6/36 or worse in both eyes; (2) the presence of diabetic retinopathy; and (3) the presence of maculopathy, preproliferative and proliferative retinopathy, grouped as severe retinopathy. Insulin treatment was associated with all outcome variables, duration from diagnosis of diabetes with retinopathy of all forms, and increasing age with reduced vision and severe retinopathy. Hypertensive diabetic patients were twice as likely to have reduced vision as compared with non-hypertensive diabetic individuals.

Adult↗
PubMed1996

The acute and long-term ocular effects of accelerated hypertension: a clinical and electrophysiological study.

Thirty-four patients with accelerated hypertension were clinically examined. The visual evoked potential (VEP) and electroretinogram (ERG) were recorded: acutely in 12 patients, being repeated in 7 patients up to 6 months later. In the remaining 22 patients these tests were performed 2-4 years after presentation. Visual acuity was < or = 6/12 in 22 of 68 (32%) eyes at presentation and < or = 6/12 in 10 of 58 (19%) eyes at follow-up. The cause of severest loss of vision appeared to be anterior ischaemic optic neuropathy, found in 3 cases. During the acute stage 11 patients (92%) had abnormal VEPs and all had abnormal ERGs. The group mean P100 latency, of the 7 patients (14 eyes) seen acutely and followed up at 6 months, was 123.8 ms with significant recovery of latency (p < 0.005) to 110.9 ms. The ERGs, however, remained reduced and delayed. In those patients recorded 2-4 years after their acute episode the VEP was abnormal in only 2 patients (9%); group mean P100 latency was 109.1 ms. However, 18 patients (82%) had abnormal ERGs. We suggest that during the acute stage of accelerated hypertension there is a high incidence of ischaemic optic neuropathy that usually resolves but can cause a permanent anterior ischaemic optic neuropathy, in addition to vascular retinopathy that persists.

Acute Disease↗
PubMed1996

Treatment of thyrotoxicosis resistant to carbimazole with corticosteroids.

We report two patients whose thyrotoxicosis failed to respond to conventional treatment with carbimazole. The patients remained persistently hyperthyroid, both clinically and biochemically, despite several months of carbimazole therapy at the maximum recommended doses. Prednisolone 20 mg per day was then given in addition to the antithyroid drug and a dramatic response observed in both cases. They were then successfully treated with radioiodine. Prednisolone has not been previously used to treat patients with hyperthyroidism who have not responded to thionamide drugs. Our experience suggests that corticosteroids may be potentially useful for controlling thyrotoxicosis in combination with carbimazole before definite treatment can be instituted.

Adult↗
PubMed1996

Hypertensive retinopathy: a review of existing classification systems and a suggestion for a simplified grading system.

With the advent of sophisticated ophthalmological investigations and a better understanding of the pathophysiology and clinical or prognostic correlates of the fundal lesions in hypertension, the limitations of early classification schemes using simple ophthalmoscopic appearances are increasingly apparent. This review describes the existing classification systems for hypertensive retinopathy and their limitations, as well as the pathophysiological effects of hypertension on the retinal vasculature. A new and simpler grading system for hypertensive retinopathy is proposed, dividing the features according to prognosis into two categories of non-malignant vs malignant hypertension. Such a simpler, updated system for our medical practice has been long overdue.

Humans↗
PubMed1996

Effects of dietary sodium substitution with potassium and magnesium in hypertensive type II diabetics: a randomised blind controlled parallel study.

We have previously demonstrated that modest sodium restriction has a hypotensive effect in hypertensive diabetic subjects. A randomised blind controlled study has therefore been performed to study the effect of replacement of added salt intake using a salt substitute (50% NaCl, 40% KCL, 10% Mg2+, supplied by Cederroth, Sweden), compared to added whole salt intake over a 9 month period of 40 hypertensive Type II diabetic subjects (mean age 62.5 +/- 7.8 years; 24 males and 16 females). After 3 months, there was a significant reduction in systolic blood pressure (SBP) in the salt substitution group (163.2 +/- 24.2 to 153.6 +/- 20.8 mm Hg; P < 0.03) which was maintained at 9 months, when compared to the whole salt group (151.5 +/- 20.6 vs 173 +/- 18.9 mm Hg; P < 0.05). No significant changes were observed in mean weight, fasting lipid or insulin levels or diabetic control (measured by glycosylated haemoglobin). A greater number of patients were withdrawn during the study period owing to consistent BP > 160/95 in the whole salt group (n = 10) compared to salt substitute (n = 4). No significant changes were observed in diastolic pressure, 24-h urine sodium or magnesium excretion, but urine potassium was significantly increased in the salt substitute group (58.8 to 77.3: P < 0.05). The results of this study suggest that substitution of sodium, by potassium and magnesium, produces a clinically significant reduction in SBP in hypertensive Type II diabetic patients, and should be a useful antihypertensive therapy in this patient group.

Aged↗
PubMed1995

Fibrinogen, cholesterol and smoking as risk factors for non-arteritic anterior ischaemic optic neuropathy.

Non-arteritic anterior ischaemic optic neuropathy (AION) is thought to be due to occlusion of the posterior ciliary circulation. Raised lipid and fibrinogen concentrations are recognised risk factors for vessel occlusion in cardiovascular disease and stroke but, although suspected as risk factors in non-arteritic AION, they have not been studied in this condition. We therefore performed a case-control study on 41 patients with non-arteritic AION, looking at these and other atherosclerotic risk factors. The odds ratio of cholesterol being > 6.5 mmol/l in non-arteritic AION was 2.7 (95% confidence interval 1.09 to 6.65; p < 0.05) and of fibrinogen being > 3.6 g/l was 5 (2.66 to 9.39; p < 0.05). Smoking was also found to be significantly associated with non-arteritic AION, the odds ratio being 16 (3.23 to 79.23; p < 0.001). These were the only risk factors found to be significantly associated with non-arteritic AION. This raises the possibility that appropriate medical management of these factors could be given to prevent recurrence in the fellow eye.

Aged↗
PubMed1995

Severe hypertension with lone bilateral papilloedema: a variant of malignant hypertension.

Patients with severe hypertension with retinoscopic bilateral papilloedema only are not classically regarded as having malignant hypertension (MHT). We have encountered 23 such patients between 1965-1993, whilst over a similar period we have seen 315 patients who fulfilled the conventional criteria for MHT with bilateral retinal haemorrhages, exudates with or without papilloedema. We hypothesised that patients with "lone" papilloedema and severe hypertension were suffering from a disease which was identical in aetiology and outcome to conventional MHT. There were no significant differences in age, mean blood pressure, proteinuria or renal function at presentation, ethnic composition, smoking status and followup blood pressure control between the papilloedema group and those presenting with conventional MHT. Clinical features at presentation in the papilloedema only group included strokes in 4, visual disturbance in 2, headaches in 3 and heart failure in 1 patient. Many patients however had no complications at presentation. After a mean followup of 59.8 months, of the "lone" papilloedema group, 7 patients (30.4%) were still alive, 1 patient was on renal dialysis therapy, 13 were dead (56.5%) and 2 (8.7%) were lost to followup. The commonest causes of death were stroke in 4 patients, renal failure in 4 and heart disease in 2. This was a similar pattern of mortality to those patients with "conventional" MHT. Lifetable analyses showed a median survival of 35.9 months for the papilloedema group which was significantly worse than the 108.7 months for the conventional MHT group (Lee-Desu statistic 4.04, p = 0.045). We suggest that patients with high blood pressure and lone bilateral papilloedema may comprise a hitherto unrecognised subgroup of patients with MHT. Once intracerebral pathology has been excluded, these patients need to be treated as aggressively as those with MHT.

Adult↗
PubMed1993

Are there medical conditions specifically underlying the development of rubeosis in central retinal vein occlusion?

Two hundred and thirty five patients with central retinal vein occlusion (mean age 64.9 years, 95% CI (63.3, 66.5) years), comprising 221 white Europeans, 10 Asians and 4 West Indians) were studied over a 7 year period of whom 13.2% (n = 31) developed rubeosis (mean age 70.1 years, 95% CI (66.3, 73.9) years; all white Europeans). Comparisons were made with 31 of the original 235 CRVO patients who did not develop rubeosis, and who were individually matched for age, sex and ethnic origin. The 31 patients developing rubeosis were significantly older (p = 0.013) than the 204 patients not developing rubeosis (mean age 64.1 years, 95% CI (62.3, 65.9) years). There was no significant difference between the CRVO group with rubeosis and the uncomplicated matched CRVO group in the prevalence rates of hypertension (64.5% vs. 45.2%), hyperlipidaemia (48.4% vs. 38.7%) or diabetes mellitus (9.7% vs. 12.9%). We conclude that neovascular glaucoma is more likely to occur in older subjects with CRVO.

Adult↗
PubMed1993

Management of hyperlipidaemia: guidelines of the British Hyperlipidaemia Association.

There is considerable evidence to suggest that the identification and treatment of dyslipidaemia will reduce the risk of premature CHD, i.e. before the age of 65. Diagnosis of the cause of raised plasma lipid levels will enable appropriate decisions to be taken with regard to management. The cornerstone of treatment is nutritional counselling and attention to other major risk factors for CHD, particularly smoking and hypertension. For a small percentage of patients with severe hyperlipidaemia drug therapy is indicated. Appropriate drug choices need to be made based on the particular lipid abnormality to be treated. In general those patients with clinical vascular disease are treated more aggressively than those where the aim is primary prevention. More research is needed to determine individual risk more precisely and to allow proper targeting of therapy. Genetic factors, qualitative changes in lipoproteins, lipoprotein (a), fibrinogen, and other coagulation and thrombotic factors are likely to be important in individual risk assessment. There is no doubt that more information is needed from prospective studies of lipid-lowering therapy in terms of risk benefit for affected individuals. Hopefully the major studies currently underway will fill some of the gaps in our knowledge. Until then aggressive therapy with drugs should be reserved for those at highest risk where the benefit is likely to be greatest.

Cholesterol, Dietary↗
PubMed1993

Malignant change in dermatitis artefacta.

Dermatitis artefacta is a chronic skin lesion produced by self-trauma. Avoidance of further trauma, topical steroids and psychological therapy all play a part in the treatment of such lesions. Unresolved lesions may become large and disfiguring and subject to infection. We report a case of one such lesion in an elderly woman who persistently excoriated a cholecystectomy scar over 40 years. Malignant transformation occurred in a manner analogous to the neoplastic change observed in other types of chronic ulcer (Marjolin's ulcer). The squamous cell carcinoma presented with widespread metastases from which the patient eventually died. Recent literature concerning Marjolin's ulcers is reviewed and it is noted that this is the first reported case of death caused by malignant change in dermatitis artefacta.

Aged↗
PubMed1992

Diabetes mellitus and retinal vein occlusion in patients of Asian, west Indian and white European origin.

The incidence of retinal vein occlusion (RVO) is known to be related to several cardiovascular risk factors including diabetes mellitus, hypertension and hyperlipidaemia. We have assessed the prevalence of these risk factors in Caucasian (N = 536, mean age = 65.21 years), West Indians (N = 24, mean age = 57.3 years) and Asian (N = 28, mean age = 51.4 years) patients presenting with RVO. We found no significant differences between the three groups in the distribution of hyperlipidaemia, but diabetes mellitus was more common amongst both the Asians and W. Indians (10% v 29% and 38%, p < 0.01 and p < 0.001). Hypertension was also more common in both the Asians and the West Indians (59% v 64% and 83% m p < 0.001 and p < 0.0001). The Asians and West Indians presenting with RVO were significantly younger and had significantly higher body mass index than their Caucasian counterparts (Ethnic origin, BMI, mean age: Asian, 28.1 +/- 4.3, 51.5 +/- 12.3 years; West indian: 30.2 +/- 7.7, 57.3 + 10 years; White: 24.8 +/- 4.2, 65.2 +/- 11.4 years). In this study RVO occurred at a younger age in Asians and West Indians, and was associated with a greater prevalence of diabetes mellitus and hypertension. The prevalence of hyperlipidaemia was no different in the three groups.

Age Factors↗
PubMed1992

Risk factors for peripheral vascular disease in hypertensive subjects with type 2 diabetes mellitus.

Possible factors predisposing to peripheral vascular disease (PVD) in hypertensive subjects with Type 2 diabetes mellitus were studied. Details of age, sex, duration of diabetes, blood pressure, and smoking habit were recorded in 180 subjects of either White, West Indian Black or Asian ethnic origin. Glycosylated haemoglobin, fasting serum total cholesterol, total high density lipoprotein (HDL), HDL2, low density lipoprotein (LDL-cholesterol), and triglycerides were measured in all subjects. Peripheral vascular disease was defined as an ankle/brachial systolic pressure < 1.0 as measured by the Doppler technique. Multivariate analysis was performed and the following factors were identified as being strongly associated with the presence of PVD with a statistical significance of p < 0.001; LDL-cholesterol, total HDL-cholesterol, age, male sex, diet or oral hypoglycaemic therapy, diastolic blood pressure, and of p < 0.003; systolic blood pressure. When blood pressure was excluded from the analysis the other factors retained their predictive value. We conclude that hypertension and dyslipidaemia are important risk factors for peripheral vascular disease in Type 2 diabetes mellitus.

Blood Pressure↗
PubMed1991

Long-term follow-up of and underlying medical conditions in patients with diabetic exudative maculopathy.

Recent reports of risk factors for and survival of patients with diabetic retinopathy do not include exudative maculopathy as a separate entity. We therefore studied a group of hypertensive Type II diabetic subjects with exudative maculopathy (n = 26) compared to a carefully matched hypertensive diabetic comparison group without retinopathy (n = 26) over seven years. Diabetic maculopathy patients had higher mean diastolic blood pressure (101.6 +/- 14 versus 94.8 +/- 10 mmHg, p less than 0.05), serum cholesterol (6.65 +/- 2.2 versus 5.9 +/- 1.31 mmol/l), HDL2 subfraction levels (0.46 +/- 0.23 versus 0.32 +/- 0.18 mmol/l) and a higher prevalence of hyperlipidaemia (54% versus 35%) compared to the comparison group. After seven years, the maculopathy group showed a strikingly higher prevalence of renal failure and nephrotic syndrome (42% versus 8%, p less than 0.05) and of macroproteinuria (58% versus 15%, p less than 0.01) compared to the comparison group. Mortality and cardiovascular disease event rate was 12% and 38% in the maculopathy and 15% and 31% respectively in the comparison group. We conclude that although mortality is not significantly higher in diabetics with exudative maculopathy, proteinuria, renal failure and nephrotic syndrome may be associated features on long term follow-up. Hypertension and hypercholesterolaemia may also be risk factors in the development of diabetic maculopathy.

Adult↗