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Biomedical subjects

R Klein

Publications and source records attributed to R Klein.

At least 451 records · Page 25Linked to original sources
PubMed1994

Ten-year incidence of visual loss in a diabetic population.

PURPOSE: The purposes of this study are to estimate the 10-year incidence of blindness and visual loss in a diabetic population, examine risk factors for visual loss, and examine temporal trends in rates of blindness and visual loss. METHODS: The design is a population-based cohort study, which includes 891 younger-onset persons with diabetes, 485 persons with older-onset diabetes who are taking insulin, and 502 persons with older-onset diabetes who are not taking insulin and who participated in baseline, 4-year, and 10-year examinations. The main outcome measures are incidence of blindness (visual acuity, 20/200 or worse), doubling of the visual angle, and visual impairment (visual acuity, 20/40 or worse). RESULTS: The 10-year incidences of blindness were 1.8%, 4.0%, and 4.8% in persons in the younger-onset, older-onset taking insulin, and older-onset not taking insulin groups, respectively. Respective 10-year rates of visual impairment were 9.4%, 37.2%, and 23.9%. Rates for doubling of the visual angle were similar. Doubling of the visual angle was more common in women with older-onset diabetes and in persons with younger-onset and older-onset diabetes who were taking insulin and who had higher glycosylated hemoglobin or proteinuria levels. The presence of macular edema or more severe retinopathy was associated with more visual loss in all three groups. Smoking was associated with visual loss in persons with younger-onset diabetes, and systolic blood pressure was associated in persons with older-onset diabetes who were taking insulin. Rates of blindness and doubling of the visual angle decreased in persons with younger-onset diabetes in the second part of the follow-up. In the older-onset groups, only the rate of blindness declined. These decreases could not be explained entirely by treatment or mortality. CONCLUSIONS: Several modifiable risk factors are associated with loss of vision. Although visual loss is still common in this diabetic population, the incidence of blindness may be decreasing.

Adolescent↗
PubMed1994

Relation between lens opacities and vitamin and mineral supplement use.

PURPOSE: The authors evaluated the cross-sectional and longitudinal relations between lens opacities and intake of vitamins and minerals in supplements. METHODS: Type and quantity of vitamins and minerals taken currently and 10 years before interview were obtained in a population-based sample of persons in the Nutritional Factors in Eye Disease Study (n = 2152). RESULTS: In persons without diabetes, regular use of multivitamin preparations 10 years in the past was associated with decreased risk for nuclear sclerosis (odds ratio [OR], 0.6; 95% confidence interval [CI], 0.5, 0.8) and increased the risk for cortical opacities (OR, 1.6; CI, 1.1, 2.2). In persons with diabetes, past multivitamin use was not associated with nuclear sclerosis (OR, 1.1; CI, 0.4,2.7) but with decreased risk for cortical opacities (OR, 0.1; CI, 0.0, 0.9). Cross-sectional associations with current intake of supplements were weaker, but in the same direction. Multivitamin use was not cross-sectionally or longitudinally related to posterior subcapsular cataract in persons with or without diabetes. CONCLUSION: Use of vitamin supplements is longitudinally associated with nuclear and cortical opacities. However, the direction of the association is influenced by the type of opacity and diabetes status.

Adult↗
PubMed1994

Ocular factors in the incidence and progression of diabetic retinopathy.

PURPOSE: To investigate the association of intraocular pressure (IOP), ocular perfusion pressure, and myopia with the incidence and progression of diabetic retinopathy. METHODS: The design is a cohort study of a population-based sample (n = 1210) of persons with younger-onset diabetes (diagnosis was made before 30 years of age, and subjects were taking insulin) and a random sample (n = 1780) of persons with older-onset diabetes (diagnosis made after 30 years of age). Baseline and 4-year follow-up examinations were completed by 891 younger-onset and 987 older-onset persons. Retinopathy was graded from stereoscopic fundus photographs. Endpoints were incidence of retinopathy, progression of retinopathy, and progression to proliferative diabetic retinopathy (PDR). Ocular perfusion pressure was calculated from IOP and blood pressure. Myopia was a refractive error of -2 diopters or less. RESULTS: In univariate analyses, ocular perfusion pressure was associated with incidence of retinopathy (P < 0.005), progression of retinopathy (P = 0.07), and progression to PDR (P < 0.001) in the younger-onset group but not in older-onset subjects taking or not taking insulin. Intraocular pressure and myopia were not associated with any endpoint in any group. Using logistic regression to control for covariates, ocular perfusion pressure was significantly associated only with incidence of retinopathy in younger-onset persons. The odds ratio for a 10-mmHg increase in ocular perfusion pressure was 2.13 (95% confidence interval, 1.30-3.50). Also, myopia was protective for progression to PDR in younger-onset persons with an odds ratio of 0.40 (95% confidence interval, 0.18-0.86). CONCLUSIONS: These results suggest that pressure phenomena may be related to the development of retinopathy in younger-onset persons. This would have implications for treatments affecting both IOP and blood pressure.

Adult↗
PubMed1994

The relation of socioeconomic factors to the incidence of proliferative diabetic retinopathy and loss of vision.

PURPOSE: To investigate the relations between socioeconomic factors and the incidence of proliferative retinopathy and loss of vision. METHODS: A population-based sample of younger-onset persons with diabetes 25 years of age or older (n = 334) and older-onset persons with diabetes (n = 906) was followed over a 4-year period. Education, occupational status, employment status, and marital status were measured at baseline and follow-up. Main outcome measures were incidence of proliferative retinopathy and loss of vision measured using standard protocols. RESULTS: Proliferative retinopathy was more likely to develop in younger-onset women with less education than in those with more education; no relation was found in the older-onset group. Education was associated inversely with incidence of loss of vision in younger-onset women and older-onset men. CONCLUSION: These data suggest that education is associated with the development of loss of vision, independent of other risk factors. The associations vary between men and women and between younger-onset and older-onset people with diabetes. Further understanding of these relationships may lead to interventions to prevent loss of vision in people with diabetes.

Adult↗
PubMed1994

Antimitochondrial antibody profiles in patients with primary biliary cirrhosis before orthotopic liver transplantation and titres of antimitochondrial antibody-subtypes after transplantation.

Four antimitochondrial antibody profiles (A-D) have been defined in primary biliary cirrhosis according to the presence of antibodies to M2, M4, M8, and M9 in ELISA and the complement fixation test: A: anti-M9 positive in ELISA and western blot, B: anti-M9 and/or anti-M2 positive in ELISA, C: anti-M2, -M4 and/or -M8 positive in ELISA, D: anti-M2, -M4, and/or -M8 positive in ELISA and complement fixation test. These profiles predict the outcome of primary biliary cirrhosis in the early stages and reflect differences in the natural course of the disease (benign versus progressive). In this study sera from 29 patients with advanced primary biliary cirrhosis who had received liver transplant were retested before and after orthotopic liver transplantation. Twenty-eight were antimitochondrial antibody/anti-M2 positive, and one patient had only antibodies to nuclear dots in the immunofluorescence test on cell cultures. When the antimitochondrial antibody-profiles in these 28 anti-M2 positive patients were analysed, it became evident that 26 of them belonged to subgroup C or D before orthotopic liver transplantation. Two patients had profile B; one had high titres of antinuclear and smooth muscle antibodies indicating an overlap syndrome between primary biliary cirrhosis and autoimmune chronic active hepatitis. The other patient had antibodies to nuclear dots in association with anti-M2. None of the patients had profile A. Antibody titres were studied after orthotopic liver transplantation in 23 of the 28 patients who survived for 1 to 13 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Induction of autoimmune phenomena in patients with chronic hepatitis B treated with gamma-interferon.

All interferons display antiviral properties, but gamma-interferon especially has an immunomodulatory effect and may induce autoimmune phenomena. Therefore the formation of autoantibodies was investigated in patients with chronic hepatitis B treated with gamma-interferon. Eleven patients (all HBs-Ag and HBe-Ag positive) were treated for 6 months with recombinant gamma-interferon. The following antibodies were tested: anti-nuclear antibodies, smooth muscle antibodies, anti-actin, anti-mitochondrial antibodies of subgroup anti-M2 and anti-M9 as well as naturally occurring antibodies, antibodies to liver-kidney microsomes, vascular endothelial cell antibodies, sarcolemmal antibodies, parietal cell antibodies, thyroglobulin antibodies and antibodies to laminin and keratin. All patients produced autoantibodies during therapy. The maximum antibody formation and the highest titres were observed in the period between the 3rd and 6th month after therapy began. The cumulative frequencies of the different antibody specificities were as follows: n = 6 anti-nuclear antibodies, n = 7 smooth muscle antibodies, n = 1 anti-actin, n = 12 antibodies to laminin or keratin, n = 6 endothelial cell antibodies/sarcolemmal antibodies, n = 6 anti-mitochondrial antibodies, n = 1 antibodies to liver-kidney microsomes, n = 2 thyroglobulin antibodies, n = 4 parietal cell antibodies. Antibodies persisted in six patients over a period of 3 months (two cases of parietal cell antibodies and one case of antibodies to liver-kidney microsomes) and were still detectable in three patients 6 months after therapy. In three patients new antibody formation occurred 1 month after therapy. So far, clinical signs of an autoimmune disorder have not appeared in any of the patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1994

Photorefractive keratectomy to correct astigmatism with myopia or hyperopia.

Excimer laser photorefractive keratectomy as a means to flatten the central cornea has generated considerable interest. With this technique radial symmetric ablations can be performed to correct myopic refractive errors and excise superficial corneal pathology. We developed a technique that uses toric ablation to correct astigmatism. A new mask was designed for the MEL 60 Aesculap-Meditec excimer laser. The mask can be rotated regularly over 360 degrees. By varying the angular distances, the surgeon can increase ablation depth in any desired meridian. As a result, both cylindrical and spherical errors can be corrected in one procedure. Seventy-three eyes with either simple, myopic, mixed, or irregular astigmatism were treated. In each category of astigmatism, the surgery reduced the spherical component as well as the overall mean preoperative cylindrical refraction. Our findings suggest that this technique is a safe and effective procedure for correcting different types of astigmatism.

Adolescent↗
PubMed1994

Antiphospholipid antibodies in cerebrovascular ischemia and stroke in childhood.

We report on eight children who suffered from cerebrovascular ischemia or stroke at the age of 2 or up to 11 years. Antiphospholipid antibodies (APLA) were detected in two cases during the ischemic event and in six cases during follow-up examinations (after six weeks or within a span of six years). In two patients multiple stenoses of basal cerebral arteries were found; one of them suffered from moyamoya syndrome. The acute hemiplegia in one patient was linked to an asymptomatic mycoplasmal infection and APLA. In three cases, one of the parents was also APLA-positive. Seven patients were treated with acetylsalicylic acid, and in four cases immunoglobulin infusions were given. Transient ischemic attacks subsided after the child with the moyamoya syndrome received immunoglobulins. No effect of medication could be established in the other children. The concept of the antiphospholipid syndrome is still evolving. As none of the common risk factors pertaining to strokes in adults apply to children, pediatric research may offer a suitable platform for specific investigations on the causal, pathogenetic role of APLA. We propose that all children suffering from stroke or transient ischemic attacks should be tested for APLA.

Antibodies, Antiphospholipid↗
PubMed1994

Role of neurotrophins in mouse neuronal development.

During vertebrate development, naturally occurring neuronal cell death is regulated by target-derived peptide factors, called neurotrophins. A recent series of papers describe the phenotypes of germline-targeted mutant mice deficient in neurotrophins and their receptors. Histological analysis of these mice for the first time has provided knowledge about the specific neuron populations that are dependent on neurotrophin action for development. Mice deficient for nerve growth factor (NGF) and its high-affinity receptor, encoded by the trkA proto-oncogene, suffer from complete loss of sympathetic neurons and sensory neurons responsive to temperature and pain. Mice deficient for brain-derived neurotrophic factor (BDNF) and its receptor, encoded by the trkB gene, display loss of sensory neurons responsive to tactile stimuli. In addition, trkB mutant mice experience loss of motor neurons indicating a possible specific function of the second TrkB ligand, neurotrophin-4 (NT-4), in motor neuron development. Mice deficient for neurotrophin-3 (NT-3) and its receptor, encoded by the trkC gene, show abnormal movements caused by the loss of sensory proprioceptive neurons.

Animals↗
PubMed1994

Self-rated health and mortality in people with diabetes.

OBJECTIVES: This study examined whether self-rated health is an independent and significant predictor of mortality in people with diabetes, using data collected in the Wisconsin Epidemiologic Study of Diabetic Retinopathy. METHODS: Participants were asked to rate their health in comparison with others their age. A proportional hazards model was used to regress survival time on self-rated health and a number of covariates measuring physical health. RESULTS: People with younger onset diabetes (n = 891) who rated their health relative to their peers as "worse" or "don't know" were no more likely to die than those rating their health as "the same" or "better" when physical health status was controlled. In contrast, those with older onset diabetes (n = 987) who rated their health as "worse" or "don't know" were almost twice as likely to die as those rating their health as "the same" or "better" when physical health status was controlled. CONCLUSIONS: Self-rated health is a significant predictor of mortality in people with older onset diabetes but not in those with younger onset diabetes when physical health status is controlled.

Adult↗
PubMed1994

A pictorial visual analog scale for rating severity of childhood asthma episodes.

The purpose of this study was to determine whether the use of pictorial anchors improved a visual analog scale (VAS) designed to assess asthma episodes. The sample consisted of 77 children with moderate to severe asthma attending a summer camp. They rated one of two VASs, either nonpictorial (39 subjects in year 1) or pictorial (38 subjects in year 2), three times a day for 2 weeks to report the severity of their asthma symptoms. Immediately after the subjects rated the VAS, pulmonary function testing was obtained. The mean VAS scores increased 64% using the pictorial VAS while the mean PEFRs in the 2 years were almost identical, suggesting that changes on the VAS were not due to differences in pulmonary functioning. For boys, the increase in individual mean VAS score in year 2 using the pictorial VAS was 44%; for girls, the increase in individual mean VAS scores was 112%. Use of a pictorial VAS increases the range of severity of symptoms reported by children with asthma. The instrument may be a useful tool in the systematic quantifiable assessment of subjective symptomatology in pediatric asthma.

Adolescent↗
PubMed1994

[Drug therapy of acute inner ear hearing loss in childhood and adolescence].

Sensorineural hearing loss in early childhood may severely interfere with normal speech and language development. This by itself requires pursuit of an effective therapeutic procedure. Here we report the results of therapy with a rheological agent and procaine-HCl with or without the addition of steroids. Immunological testing was also studied for possible circulating antibodies in sera of affected children. Retrospective analysis of therapeutic results showed that the therapeutic procedure employed may be beneficial, since hearing improved considerably in some cases. Since an autoimmune-related sensorineural hearing loss has been postulated for some years, results presented here could be used as an argument for the presence of antibody-related inner ear disorders in early childhood. These findings suggest that circulating antibodies in children suffering from sensorineural hearing losses produce an inflammatory process involving inner ear structures. Circulating antibodies may also indicate a secondary immune reaction. However, sensory hearing loss occurring in early childhood may be steroid sensitive.

Adolescent↗
PubMed1994

[Retinal vasculitis and antiphospholipid antibodies].

Antiphospholipid antibodies (APAb) are often found in systemic lupus erythematosus (LE) (secondary antiphospholipid syndrome), leading to arterial or venous thrombosis. In primary antiphospholipid syndrome other LE-associated symptoms are not detectable. We present the clinical course and therapy of three patients with this rarely reported disease, discussing immunopathology and therapy. Three young patients (28, 29 and 31 years) were seen at the university eye clinic, presenting severe occlusive vasculitis with vitreal haemorrhages and/or thrombosis. The first patient did not respond to any therapy (various immunosuppressives, plasma-pheresis, laser coagulation) and ended up with defective light perception in both eyes. The second patient also had light perception as final outcome in spite of acetylsalicylic acid, steroids and immunosuppression. The third patient established complete reperfusion on an arteriovenous occlusion after haemodilution and acetylsalicylic acid. Antibodies directed against phospholipids interfere with the blood clotting system in many ways (activation and aggregation of thrombocytes, endothelial function, coagulation cascade). The optimal therapy of this severe disease is unclear, suggesting that acetylsalicylic acid seems to be important, while the effect of immunosuppression or steroids is uncertain.

Adult↗