[Influence of good blood sugar control in diabetic retinopathy].
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Blood Glucose↗
Biomedical subjects
E M Kohner
Publications and source records attributed to E M Kohner.
A study of platelet-relevant parameters in patients with diabetic microangiopathy.
In 16 diabetic patients with microangiopathy, survival of 111In-labelled autologous platelets, mean platelet volume, megathrombocyte index, spontaneous and ADP-induced platelet aggregation, platelet retention, beta-thromboglobulin, von Willebrand factor and factor VIII-related antigen were measured; the splenic uptake of radioactive label was quantitated in six patients. Compared with normal subjects, increased platelet aggregation (p less than 0.01), von Willebrand factor (p less than 0.02) and factor VIII-related antigen (p less than 0.02) were observed. Platelet survival was shortened in two patients. It correlated inversely with the splenic radioactivity uptake (r = -0.95; p less than 0.01), suggesting that platelets ended their life in the spleen, not in the microcirculation. No significant relationships were found between the various tests performed, nor between these and the severity of microangiopathy or other clinical data. In spite of the evidence for altered platelet function in patients with diabetic microangiopathy, currently available tests are not specific enough to clarify the nature of these changes or their possible pathogenic significance.
Adult↗
Caution advised when managing diabetic retinopathy by continuous subcutaneous insulin infusion.
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Diabetic Retinopathy↗
The management of central retinal vein occlusion.
Central retinal vein occlusion is the result of outflow obstruction and is associated with a variety of medical conditions, mainly affecting the vascular system. Treatment of the coexistent medical conditions has no beneficial effect on visual outcome. Outflow obstruction has been treated by fibrinolytic agents and anticoagulants, hemodilution, and photocoagulation. None of these treatments were of value in improving or maintaining vision. Photocoagulation prevents neovascular complications in ischemic central retinal vein occlusion.
Adult↗
Severe diabetic retinopathy in adolescents.
This paper reports on 9 patients aged 13-18 years (mean 15.4) with severe diabetic retinopathy. Two patients were prepubertal and 4 were going through puberty. Hypertension was present in 2 patients, while 4 had proteinuria. Severe preproliferative disease was present in 3 patients initially and proliferative retinopathy in the remainder. In 5 this retinopathy was considered to be florid. Two patients seen prior to 1975 had pituitary ablation, while those seen after 1975 were treated by extensive argon and xenon arc photocoagulation. Proliferative lesions regressed in both groups. At the latest follow-up 7 of the 9 patients achieved a final visual acuity of 6/9 or better in at least one eye. One patient became blind. Proliferative retinopathy advances rapidly in adolescents, but photocoagulation, as used now, can maintain vision in most.
Adolescent↗
Joint contractures and diabetic retinopathy.
It has been suggested that joint contractures may be an early marker of microangiopathy, especially retinopathy, in diabetic patients. To investigate this possibility, the prevalence of contractures of the finger joints, as assessed by the painted hand technique, was compared in 106 diabetic patients without, and 105 with retinopathy (proliferative in 66%). There was an increased prevalence of contractures in those with diabetes (25.2%) as compared with an age-matched control of 106 subjects (7.5%, P less than 0.01). The prevalence of contractures was similar in those diabetics with and without retinopathy (29.5% v. 20.8%, P less than 0.1), and did not vary with the type of retinopathy. The contracture prevalence rate was also similar in those with a diabetes duration of 5 or more years (retinopathy 29.3%, no retinopathy, 30%) or of similar diabetic duration (retinopathy 20.8%, no retinopathy, 25%). Diabetic control, as assessed by HbA1, was similar in retinopathic patients with or without contractures. We conclude that although finger joint contractures are more prevalent in adult diabetic patients, they are not necessarily a reliable early indicator of the development of retinopathy of any specific type.
Adult↗
Insulin resistance and insulin deficiency in diabetic retinopathy of non-insulin-dependent diabetes.
To assess the role of insulin resistance and insulin deficiency in the pathogenesis of diabetic retinopathy in non-insulin-dependent diabetes mellitus, 13 patients with and 12 patients without retinopathy were studied. The glucose clamp technique was used to measure insulin resistance and insulin response to glucose. During the euglycemic clamp, at comparable steady-state levels of glucose and insulin, the mean glucose infusion rate, which indicates the rate of glucose utilization, was lower in the retinopathy group than in the nonretinopathy group (6.1 +/- 0.5 versus 8.1 +/- 0.7 mg . kg-1 . min-1, P less than 0.02). Growth hormone (GH) concentrations were higher in the retinopathy group 8.4 +/- 2.5 versus 2.5 +/- 0.7 microIU/ml, P less than 0.05), but they did not correlate significantly with insulin resistance, expressed as mean glucose turnover. During the hyperglycemic clamp (+7 mmol/L above the fasting plasma glucose), the insulin response in the two groups of diabetics was similar. Increased insulin resistance represents an additional factor, which together with other factors, may be important in the pathogenesis of diabetic microvascular complications.
Blood Glucose↗
Quantitative evaluation of fluorescein angiograms: microaneurysm counts.
This study describes a method for quantifying microaneurysms (MA) from fluorescein angiograms. The method was validated by the reproducibility of the number of MA in 30 angiograms read twice each by two independent observers; and by the absolute difference in MA counts between two readings by the same observer, and difference in numbers counted by two different observers. The precise location of each MA on two readings was also studied and the reproducibility of location varied from 60 to 71%, depending on the quality of the angiograms. Clinicians and technicians working in the same or in different centers obtained similar results. The coefficient of correlation between observers and between readings was satisfactory, r greater than 0.9. The method is easy to learn and the reproducibility allows for its use in clinical trials.
Aneurysm↗
[Hypertensive retinopathy].
Retinal blood vessels differ from most other vessels in the body (with the exception of those in the brain) in two important respects. The first is the presence of blood-retinal barriers, best illustrated by fluorescein angiography. The second important difference is that retinal vessels do not have sympathetic innervation and blood flow is modulated by autoregulation mechanisms. In 1939 Keith, Wagener and Barker proposed a classification system for hypertensive retinopathy which was innovative and of prognostic importance at that time. However, the different features of hypertensive and arteriosclerotic vasculopathies are not adequately distinguished by this classification system. Clinical features of accelerated hypertension are retinal haemorrhages, cotton wool-spots, hard exudates, papilloedema and increased vascular permeability. These must be differentiated from features associated with arteriosclerosis which are arteriovenous crossing changes and arterial constriction. The advantages of the Hogan classification system, based up on histopathologic and pathogenetic considerations are discussed. Other retinal vascular diseases associated with hypertension are also mentioned. Such as toxaemia of pregnancy, arterial macroaneurysm and anterior ischaemic optic neuropathy. Retinal branch vein occlusion is rather associated with arteriosclerosis than with hypertension.
Animals↗
Inverse relationship between ristocetin co-factor levels and platelet aggregation in insulin dependent diabetes.
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Adult↗
Insulin secretory response to oral glucose load, diabetic microangiopathy and diabetic control: a study in non-insulin dependent diabetics.
To study the importance of the residual insulin secretion for the degree of diabetic control and for the development of microangiopathy 55 patients with non-insulin-dependent diabetes mellitus (NIDDM) were studied. A 1 hr oral glucose tolerance test was performed at diagnosis and 5-10 yr later. At diagnosis all patients were free of microangiopathy, at reassessment 24 patients had evidence of microangiopathy, i.e. retinopathy, neuropathy or nephropathy, alone or in combination. The glucose induced increments of insulin levels (delta IRI) at reassessment correlated inversely with the degree of diabetic control, measured by Haemoglobin A1 (r = -0.466, p less than 0.01), and with the mean fasting blood glucose throughout the follow up period (r = -0.491, p less than 0.01). delta IRI at diagnosis was similar in patients with and without microangiopathy, and at reassessment, although lower in the microangiopathy group (11.2 +/- 2.1 vs. 16.4 +/- 2.1 microunits/ml, p less than 0.1). The difference between the 2 groups did not reach statistical significance. When patients were separated into those treated with diet alone and those treated with oral antidiabetic agents, delta IRI at reassessment was significantly lower in patients on oral agents (10.5 +/- 1.9 vs. 17.2 +/- 2.2 microunits ml, p less than 0.01), but the prevalence of microangiopathy was not different between 2 groups (37% and 52%, respectively). These findings show that in patients with NIDDM the residual beta cell function is important for the degree of diabetic control, but a direct relationship between the degree of insulin deficiency and the presence of diabetic microangiopathy is not established.
Administration, Oral↗
Ophthalmologic abnormalities in the hypereosinophilic syndrome.
Twelve patients with hypereosinophilic syndrome were studied to determine the frequency and type of eye involvement in this systemic disease. Four patients (33%) had visual symptoms, including blurred vision in one or both eyes, and one patient had an episode of complete blindness following cardiac surgery. Five patients (42%) had eye involvement by direct examination, and ten (83%) in fluorescent retinal angiograms. The principal defects noted were occlusions of major retinal vessels, choroidal infarct, and patchy or delayed choroidal filling. As these defects all occurred in patients with other severe systemic complications of the hypereosinophilic syndrome, including cardiologic disease, it is suggested that these lesions were the result of thromboembolic disease and that these patients should receive long-term anticoagulation. It was concluded that eye involvement is a frequent and important feature of the hypereosinophilic syndrome.
Adult↗
Is the pro-adhesive activity of plasma von Willebrand factor counteracted by a physiological inhibitor of platelet adhesiveness?
1. Abnormal plasma levels of von Willebrand factor are accompanied by abnormal platelet function in some disease states. 2. Platelet retention in glass bead columns, platelet aggregation in vitro, beta-thromboglobulin and 6-oxo-prostaglandin F1 alpha were monitored in six normal male volunteers before and after an acute rise of von Willebrand factor, as induced by the intravenous administration of 1-deamino 8-D-arginine vasopressin (DDAVP). 3. After DDAVP a steady twofold rise of von Willebrand factor occurred. Platelet retention increased by 74% immediately after DDAVP but returned to baseline values within 60-120 min. No consistent changes of the other variables were observed. 4. These results suggest that as yet unidentified mechanism(s) inhibits the pro-adhesive activity of von Willebrand factor.
Adult↗
SLE retinopathy: evaluation by fluorescein angiography.
Fifty-two patients with systemic lupus erythematosus (SLE) were examined by fluorescein angiography, and retinopathy was detected in 15. Three patterns of retinopathy were discerned: 4 patients had disc vasculitis, 6 had multiple cotton-wool spots, and 5 had a normal fundal appearance but fluorescein leakage on angiography. One patient had arterial occlusive disease with retinal neovascularisation and another had extensive venous disease. With 3 exceptions retinopathy was found only in patients with active SLE. No association was discovered between retinopathy and cerebral disease; in particular, fluorescein angiography did no assist the diagnosis of mild cerebral lupus.
Adult↗
Continuous subcutaneous insulin infusion (CSII) does not prevent progression of proliferative and preproliferative retinopathy.
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Adolescent↗
Increased platelet volume in diabetic retinopathy.
Platelet volume was measured in 30 healthy controls and 87 diabetic patients, the latter subdivided according to the absence, presence and severity of retinopathy, to investigate if platelet size is related to microangiopathy. The platelet volume of the whole diabetic population was increased (p less than 0.05) due to a higher percentage of large elements (p less than 0.05). The patients with various degrees of retinopathy had similar increases (p less than 0.05) in their platelet size, while those without complications occupied an intermediate position between normal controls and retinopathy patients. It is concluded that: (i) increased platelet size accompanies diabetic retinopathy, irrespective of its severity, and (ii) patients without this complication form a heterogeneous group, some of which already have alterations of platelet volume. The role of these abnormalities in the development and progression of diabetic microangiopathy remains to be established.
Adult↗
Genetic and immunologic factors in microvascular disease in type I insulin-dependent diabetes.
A detailed study of 133 subjects with insulin-dependent (type I) diabetes with severe microvascular disease has failed to substantiate the hypothesis that HLA factors influence the predisposition to this type of complication. A significant association between proliferative retinopathy and raised levels of circulating immune complexes was found. The distribution of insulin-binding levels in serum was similar to that in patients without complications. There was no correlation between insulin binding and the presence of immune complexes and no evidence was found that these complexes contained anti-insulin, anti-nuclear, or organ-specific antibodies. The distribution of insulin-binding levels in these subjects with diabetes of long duration was similar to that observed in 270 subjects with juvenile-onset short-duration type I diabetes. When the data were combined, significant associations between HLA-B8 and low/absent insulin binding levels were observed. HLA-BW62 was not associated with either high or low insulin-binding capacity. It is concluded that HLA genetic factors, insulin-binding capacity, and autoimmunity are unrelated to the pathogenesis of microvascular disease. Raised levels of circulating immune complexes may well be secondary to widespread tissue damage in diabetes of long duration.
Adult↗