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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The recent literature relating to the pathogenesis of diabetic retinopathy, with or without nephropathy, is critically reviewed. Particular attention is given to the (GH) growth hormone hypothesis. The various procedures of hypophysectomy are discussed including the possible ways of suppressing GH production or overproduction by drugs, especially with (MAP) medroxyprogesterone acetate. Personal results obtained with long-term administration of MAP in depot form on alternate days in 10 patients with advanced retinopathy are described. An inconstant and barely significant suppression of the GH response to insulin-induced hypoglycemia was noted in 6 cases showing that a complete pituitary inactivation had not been achieved. Therefore, the modifications observed in the fundus picture seem to have no relationship with such a condition. The features involved were Microaneurysms and Hemorrhages and Exudates. New vessels and retinitis proliterans were unaffected. Subjective improvement in visual acuity appeared to be more frequent with various possible explanations. MAP was without appreciable effect on the clinical and metabolic course of the diabetes or on renal function in cases of concomitant nephropathy. In light of these preliminary results, further investigation seems to be justified. (author's modified) (summary in ENG).
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PMID:[Trial treatment of diabetic retinopathy by inhibition of pituitary somatotropin secretion with MAP]. 112 48

Clinical, pathological and experimental studies of radiation retinopathy confirm that the primary vascular event is endothelial cell loss and capillary closure. Pericytes are less susceptible, but typically atrophy as the capillaries become non-functional. The immediate effects of radiation reflect interphase and early mitotic death of injured endothelial cells, whereas later changes may be attributed to delayed mitotic death of compromised endothelial cells as they attempt division in the ordinary course of repair and replacement. Capillary occlusion leads to the formation of dilated capillary collaterals which may remain serviceable and competent for years. Microaneurysms develop in acellular and poorly supported capillaries, predominantly on the arterial side of the circulation and adjacent to regions of poorly perfused retina. Alterations in haemodynamics produce large telangiectatic-like channels which, typically develop a thick collagenous adventitia and may become fenestrated. Limited capillary regeneration occurs, usually evident as recanalisation of arterioles or venules by new capillaries. Vitreo-retinal neovascularisation may occur where retinal ischaemia is widespread. Radiation produces an exaggerated vasculopathy in patients with diabetes mellitus, and five month streptozotocin-induced diabetic rats develop a severe ischaemic retinopathy with vitreoretinal neovascularisation when exposed to 1500 cGy of radiation. Later photocoagulation is useful in containing or reversing microvascular incompetence and vasoproliferation in some patients with advanced radiation retinopathy.
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PMID:Radiation retinopathy--clinical, histopathological, ultrastructural and experimental correlations. 207 Aug 83

We evaluated prospectively for 12 months 22 patients with late-onset diabetes mellitus and minimal retinopathy by fluorescein angiography and fluorophotometry. The study showed that early retinopathy changes were not permanent or invariably progressive, but may regress. Microaneurysm gradings worsened in 24%, improved in 14% and remained stabilized in 62%. Capillary closure worsened in 33%, improved in 10% and remained stabilized in 57%. The evolution of early diabetic maculopathy is slow and irregular, and this study has shown that vitreous fluorophotometry must be included when short follow-up periods of up to 12 months are considered. Finally, eyes with higher fluorophotometry values at entry showed significantly more deterioration during the 12-months follow-up period (p less than 0.05).
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PMID:[Follow-up of early diabetic maculopathy by angiography and fluorophotometry]. 263 61

Nailfold capillary microscopy (NCM) is a non invasive method to investigate digital microcirculation. The NCM pattern of 70 children with diabetes (duration varying from less than one month to 18 years) and of 35 healthy children was studied. Several capillary loops anomalies were observed: haemorrhages, disorganisation, dystrophies, microaneurysms. The anomalies were more frequent in children with diabetes (61.4%) than in the controls (20%; p less than 0.001). Haemorrhages and nailbed disorganisation were seen in both groups. Dystrophies were found more frequently in the diabetic group (46%) than in the controls (17%; p less than 0.01). Microaneurysms were observed only in diabetic children (27%; p less than 0.001); they were present in 18.5% of the children with a diabetes duration of less than 2 years and their frequency did not increase with the duration of the disease. Sex ratio, age and HbA1c were not different between the diabetic children with or without microaneurysms. No relationship was found between retinal angiography and NCM detection of the microaneurysms. In conclusion, NCM is able to detect frequent anomalies of the digital microcirculation, especially microaneurysms, early in the course of diabetes in children. The follow up of this pediatric population will provide further information on the prognostic value of these lesions.
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PMID:Detection by nailfold capillary microscopy of early morphologic capillary changes in children with insulin dependent diabetes mellitus. 275 18

In 1975 a prospective longitudinal study of 63 non-pubescent children with insulin-dependent diabetes mellitus (IDDM) was started in order to study the development of retinopathy. This paper presents the results of a 5- and an 8-year follow-up examination concerning the individual development of retinopathy in the patients. At the last follow-up the mean age of the patients was 21.9 years (18-23 years) and the mean diabetes duration 13.2 years (8.1-21.2 years). In 1975 only 5% had developed retinopathy. In 1980 this incidence had risen to 63% and in 1983 to 93% (14% proliferative retinopathy and 79% background retinopathy). In most patients the retinopathy developed slowly, in some patients, however, it deteriorated severely within a few years. A slight regression in the number of microaneurysms and in the number of haemorrhages was observed in a few patients. Microaneurysms seemed in all but one case to be the first pathological element in diabetic retinopathy and developed as a rule several years before other diabetic fundus manifestations occurred. Development of retinopathy was correlated to the duration of diabetes. No correlation could be demonstrated between the progression of retinopathy and the status of regulation. Retinopathy occurred only in 5 patients (8%) before puberty.
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PMID:Natural history of diabetic retinopathy in insulin-dependent juvenile diabetics. A longitudinal study. 366 Nov 47

Microaneurysms, acellular capillaries and pericyte ghosts are characteristic of diabetic retinopathy, but it is not clear what causes these lesions or whether they are causally related to each other. The distribution of microaneurysms, acellular capillaries and pericyte ghosts has been evaluated in two animal models of diabetic retinopathy, diabetic dogs (n = 25) and galactose-fed dogs (n = 12). After 5 years of diabetes or galactosemia, retinas were divided into four quadrants at the optic disk, prepared by the trypsin-digest method, and the frequency of the lesions compared among the quadrants. Numbers of lesions were expressed relative to area of trypsin-digested retina examined or to total number of capillary cells examined. Microaneurysms and acellular capillaries were not uniformly distributed across the retina in diabetes or in galactosemia, both lesions being significantly (more than two-fold) more prevalent in the superior temporal retina than in the inferior nasal quadrant of retina. In contrast, the distribution of pericyte ghosts in these same eyes was not significantly different between the quadrants. These findings suggest that pericyte loss may not be sufficient to account for the development of microaneurysms and acellular (occluded) capillaries in diabetes, and raise a possibility that the lesions occur by different mechanisms. Currently available hypotheses regarding the pathogenesis of diabetic retinopathy fail to account for regional differences in the distribution of the vascular lesions within the same retina. Local factors within the eye apparently play an important role in the response of the retinal microvasculature to hyperglycemia.
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PMID:Vascular lesions in diabetes are distributed non-uniformly within the retina. 761 20

Microaneurysms are the first features of human diabetic retinopathy that can be detected with common clinical techniques. These are found, most often, in photographic field 2 (that is, an area occupying 30 degrees of the ocular fundus centered on the middle of the macula). After the first microaneurysms develop, there will be a tendency for more to appear; however, over time many of the original microaneurysms will become no longer visible with clinical techniques, while other, newer, microaneurysms mature. After the onset of microaneurysms, several years may pass before any other diabetic retinopathic lesions develop. Lesions other than microaneurysms were uncommon in this study; the following is a list in decreasing frequency: retinal hemorrhages, soft exudates, IRMA, hard exudates, and venous beading. During the 4 years of this study, there were no other diabetic retinopathic lesions detected. The duration of insulin-dependent diabetes mellitus was related to the rate of change in microaneurysm counts. The age and sex of patients did not affect this rate of change. The accuracy of metabolic control, as determined by glycosylated hemoglobin levels, may influence this rate of change; however, this was detected only at the extremes of measurement in this study. The equipment available to most ophthalmologists can detect the earliest clinical aspects of diabetic retinopathy. These features can be quantified in a reproducible manner with standardized photographic techniques to permit satisfactory data analysis.
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PMID:The natural history of the first clinically visible features of diabetic retinopathy. 788 83

To assess the relationship between glucose and advanced glycation end products (AGE) and the relationship between AGE and retinal changes in vivo, we studied the time course of retinopathy over 12 months in trypsin digest preparations and measured glycaemia and retinal AGE in spontaneous diabetic hamsters of mild (MD) and severe (SD) phenotypes. Blood glucose levels were elevated in MD (9.44+/-0.76 mmol/l) and in SD (3 months: 24.3+/-1.4 mmol/l; 12 months: 31.7+/-0.8 mmol/l) over non-diabetic controls (NC: 7.15+/-0.25 mmol/l; p < 0.05 or less vs MD; p < 0.001 vs SD). Similar relations were found for HbA1. Retinal AGE in mild diabetes was 405+/-11.3 arbitrary units (AU) (NC 245+/-7.7; p < 0.01) after 3 months and remained unchanged. A non-linear increase of AGE over time was found in severe hyperglycaemic hamsters (466+/-21 AU after 3 months and 758+/-21 AU after 12 months; p < 0.001 vs MD). Pericyte loss in mild diabetes progressed from -26% after 3 months to 41% after 12 months (p < 0.001 vs NC). Whereas the initial pericyte loss in severely diabetic hamsters was identical to the mildly diabetic group, a higher degree of pericyte loss occurred after 12 months (-57%; p < 0.05 vs MD). Endothelial cell numbers remained unaffected by mild hyperglycaemia, but significantly increased over time in severe diabetes reaching 31.7% above controls after 12 months (p < 0.001 vs NC and MD). Microaneurysms were absent in all retinae examined. Acellular capillary segments were increased in mild diabetes (3.83+/-0.31 per mm2 of retinal area) and severe diabetes (7.83+/-0.73) over controls (1.0+/-0.23). These data suggest that a threshold of glycaemia might exist above which AGE removal systems become saturated. Pericyte loss and acellular capillary formation are associated with mild increases in blood glucose and AGE levels while endothelial cell proliferation requires higher glucose and AGE levels.
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PMID:The relationship of glycaemic level to advanced glycation end-product (AGE) accumulation and retinal pathology in the spontaneous diabetic hamster. 949 49

Diabetic eye disease is present in remote communities across Canada. A pilot study was designed to assess the feasibility of stereoscopic digital imaging to identify levels of diabetic retinopathy via teleophthalmology. Diabetic patients were assessed for diabetic retinopathy by seven field stereoscopic digital imaging through a dilated pupil. Images were transferred by satellite to a tertiary eye center for review by a retinal specialist. Images were viewed stereoscopically on a video monitor, with grading of all images using a modified Early Treatment Diabetic Retinopathy Study (ETDRS) classification. Patients found to have treatable diabetic retinopathy were transferred to a tertiary eye center for assessment and treatment by a retinal specialist. One hundred patients (199 eyes) had stereoscopic digital imaging of the retina. Microaneurysms were identified in 70 eyes, hard exudates in 31 eyes. Two eyes were identified with neovascularization of the disc (NVD) and 15 eyes with clinically significant macular edema (CSME). All eyes identified by stereoscopic digital imaging with treatable disease were confirmed by clinical examination with contact lens biomicroscopy. Stereoscopic digital imaging of the retina enables the identification of diabetic retinopathy. Further research is needed to delineate the sensitivity and specificity of stereoscopic digital imaging when compared to slide film and clinical examination.
Diabetes Technol Ther 2000
PMID:Tele-ophthalmology via stereoscopic digital imaging: a pilot project. 1146 22

The authors studied whether central retinal microaneurysm count predicts further progression of background retinopathy in juvenile onset type-1 diabetes mellitus. 94 patients (49 females and 45 males) were followed up longitudinally (8-17.5, mean 10 years) by evaluating fluorescein angiograms. Age at last examination was 17-32 years (mean age 22.4 years) and duration of diabetes was 8-22 years (mean duration 13.7 years). Microaneurysm counts and location were determined with the help of a grid consisting of three concentring circles and four radial lines (nine subfields) centered for the macula. 82% of the all microaneurysms were found inside the circle with 1500 micron radius. Participants were divided into three groups: those with no microaneurysms (1st group, n = 28) and those with 1-4 (2nd group, n = 35) and those with 5 or more microaneurysms (3rd group, n = 31) in the central circle with 600 micron radius at least one time during the whole follow up. Background retinopathy was found in 3 of 28 cases (approximately 10%) in the first group, 8 of 35 (approximately 23%) in the second group and in all the 31 patients (100%) in the third group. Proliferative retinopathy was found in the third group only. The authors suggest that the appearance of 5 or more microaneurysms in the macular area in type-1 diabetes mellitus may be sensitive indicator of the development of severe background and proliferative retinopathy. Study describes the importance of central microaneurysm count predicting further progression of background retinopathy could not be found in the available literature.
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PMID:[Prognostic significance of retinal microaneurysm number and localization in type-1 diabetes mellitus]. 1158 32


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