Changes of vascular endothelial growth factor after vitrectomy for macular edema secondary to retinal vein occlusion.

PURPOSE: To examine whether vitrectomy combined with retinal photocoagulation reduces the vitreous level of vascular endothelial growth factor (VEGF) in patients with macular edema associated with retinal vein occlusion (RVO). METHODS: The authors measured VEGF levels in vitreous samples from four eyes of four patients with RVO during vitrectomy and fluid samples obtained during revitrectomy 3 to 9 months postoperatively for complications: an epiretinal membrane in two patients, macular holes in one patient, and vitreous hemorrhage in one patient. During vitrectomy, retinal photocoagulation was performed on the ischemic region of the retina in all cases (mean of 510 shots). RESULTS: In four eyes with RVO, there was a difference in the vitreous VEGF levels between the vitreous samples obtained during vitrectomy (mean of 2692 pg/mL, range of 15.6-9040 pg/mL) and the fluid samples obtained at the time of revitrectomy (mean of 947 pg/mL, range of 15.6-3430 pg/mL). CONCLUSIONS: The results suggest that the vitreous levels of VEGF may be reduced by vitrectomy combined with retinal photocoagulation for macular edema with RVO. It may be important to reduce the vitreous levels of VEGF by vitrectomy and retinal photocoagulation for ischemic retina in macular edema with RVO.

CT colonography to detect rectosigmoid involvement in patients with primary ovarian cancer.

INTRODUCTION: We retrospectively evaluated the performance of preoperative computed tomographic (CT) colonography to detect tumor involvement of the rectosigmoid wall and predict the need for rectosigmoid resection in patients with primary ovarian cancer. METHODS: Thirty-three patients with primary ovarian cancer who underwent preoperative CT colonographic examination were evaluated. The images of the examination were analyzed and compared with the subsequent surgical findings. RESULTS: All abnormal findings (malignant infiltration of the rectosigmoid mucosa and extrinsic compression) revealed by conventional colonoscopy were correctly observed as extrinsic compression using CT colonography. The sensitivity, specificity, positive predictive value and negative predictive value of CT colonography for the prediction of rectosigmoid resection were 100%, 64.7%, 72.7%, and 100%, respectively. Though conventional colonoscopic examinations could not be completed in five patients because of the presence of extrinsic stenosis and occlusion at the sigmoid colon, CT colonography enabled the entire large bowel to be examined in these patients. CONCLUSIONS: This preliminary study showed that the CT colonographic examination is feasible and safe. CT colonography seems to have several advantages over conventional colonoscopy for the detection of rectosigmoid involvement in patients with advanced ovarian cancer. For confirmation of the efficacy of CT colonography, further large prospective studies are needed.

Fluorescein 5'-isothiocyanate-modified Na+, K+ -ATPase, at Lys-501 of the alpha-chain, accepts ATP independent of pyridoxal 5'-diphospho-5'-adenosine modification at Lys-480.

The modification of Na+,K+-ATPase with increasing pyridoxal 5'-diphospho-5'-adenosine (AP2PL) concentrations resulted in saturation of the approximately 0.5 mol AP2PL probe incorporation into the Lys-480/mol catalytic alpha-chain and reduced the Na+,K+-ATPase activity to around half without affecting the phosphorylation by acetyl phosphate (AcP), and led to increases in the AP2PL fluorescence caused by ATP and AcP. Further modification with fluorescein 5'-isothiocyanate (FITC) resulted in approximately 0.9 mol FITC probe incorporation into the Lys-501/mol alpha-chain and reduced the activity to below 5% without affecting the phosphorylation by AcP and these fluorescence increases. The ATP binding capacity of the AP2PL-FITC enzyme was shown to be at least 50% of that of the control enzyme (approximately 0.8 mol/mol alpha-chain). This is the first direct demonstration that Na+-bound FITC-modified enzymes accept ATP with an affinity for ATP (K(1/2) > 150 microM) reduced by two orders of magnitude. The data also suggest half site reactivity of Lys-480 as to AP2PL and all site reactivity of Lys-501 as to FITC in the catalytic subunits.

Angiotensin II and vascular endothelial growth factor in the vitreous fluid of patients with proliferative diabetic retinopathy.

AIMS: To investigate the correlation between the level of angiotensin II and vascular endothelial growth factor (VEGF) in the vitreous fluid and the severity of proliferative diabetic retinopathy (PDR). METHODS: During vitreoretinal surgery at the Tokyo Women's Medical University, vitreous fluid samples were obtained from 51 eyes of diabetic patients with PDR, six eyes of diabetic patients without retinopathy, and 16 eyes of non-diabetic patients with ocular disease (controls). The VEGF levels in vitreous fluid and plasma were determined by enzyme linked immunosorbent assay, while angiotensin II levels were measured by radioimmunoassay. RESULTS: The vitreous fluid levels of VEGF and angiotensin II were significantly higher in patients with PDR than in non-diabetic patients or diabetic patients without retinopathy (all p<0.0001). The vitreous fluid level of angiotensin II was significantly correlated with that of VEGF (p<0.0001), and the vitreous concentrations of both VEGF and angiotensin II were significantly higher in patients with active PDR than in those with quiescent PDR (p<0.0001 and p=0.0005, respectively). CONCLUSION: The authors found that both angiotensin II and VEGF levels were significantly higher in the vitreous fluid of patients with PDR than in that of non-diabetic patients or diabetic patients without retinopathy, and that the levels of both angiotensin II and VEGF were elevated in the active stage of PDR. These findings suggest that angiotensin II contributes to the development and progression of PDR in combination with VEGF.

Risk evaluation of outcome of vitreous surgery for proliferative diabetic retinopathy based on vitreous level of vascular endothelial growth factor and angiotensin II.

AIMS: To ascertain whether measurement of the vitreous fluid levels of vascular endothelial growth factor (VEGF) or angiotensin II (Ang II) could predict the outcome of vitreous surgery in patients with proliferative diabetic retinopathy (PDR). METHODS: A prospective observational case study was performed in 61 consecutive patients (61 eyes) with PDR who underwent vitreoretinal surgery. Vitreous fluid samples were obtained during surgery. The VEGF level in vitreous fluid and plasma was determined by enzyme linked immunosorbent assay, while the Ang II level was measured by radioimmunoassay. Patients were prospectively followed for 6 months and the postoperative outcome was analysed by logistic regression analysis. RESULTS: No improvement and/or progression of PDR was seen in 15 (25%) of the 61 eyes. Vitreous levels of VEGF and Ang II were significantly higher in eyes with progression of PDR than in eyes with regression of PDR (p = 0.0044, and p = 0.0178, respectively). Multivariate logistic regression analysis showed that the vitreous VEGF level increased along with the progression of PDR after vitreous surgery (odds ratio 2.48, p = 0.0008). CONCLUSION: A high vitreous fluid VEGF level is associated with a significant risk of postoperative progression of PDR. The vitreous level of VEGF at the time of surgery may be a useful predictor of the outcome.

Present status of ophthalmological care for diabetic patients in Japan.

PURPOSE: To investigate the present status of diabetic care provided by ophthalmologists working in hospitals and private clinics in Japan. METHODS: Questionnaires were mailed to 315 ophthalmologists. There was a return rate of 73%. RESULTS: Problems identified in the clinics were: (1) many diabetic patients who complain chiefly of ophthalmological symptoms voluntarily request their first ophthalmological examination; (2) appropriate cooperation between ophthalmologists and physicians is not established; (3) assessing the level of blood glucose control is difficult; and (4) scheduling of appointments is inadequate. Moreover, (1) inadequate handling of patients who discontinue their ophthalmological examinations, and (2) the lack of an established patient education program were seen as problems common to both hospitals and clinics. CONCLUSIONS: For the resolution of these problems, comprehensive countermeasures should be developed urgently by medical associations, medical administrators, and other relevant entities.

Correlation between progression of diabetic retinopathy and blood glucose control.

The relationship between the progression of diabetic retinopathy and consecutive blood glucose control evaluated by glycosylated hemoglobin (HbA1) values was statistically analyzed based on 422 eyes of 211 diabetic subjects who were followed up 2 years or more. The Cox regression model (proportional hazard model) with HbA1, as a time-dependent covariate was applied in the analysis. The cumulative effect and the relative risk of HbA1 affecting the progression of diabetic retinopathy was estimated. The effect of the moving average of HbA1 values for the previous 1-30 months on the progression of retinopathy was assessed to investigate the cumulative effect of HbA1. The cumulative effect of HbA1 on the progression of diabetic retinopathy was significant when the time span of the moving average was 6 months or more than 6 months. The moving average of HbA1 value for 7 months was most relevant to the retinopathy progression. The relative risk corresponding to the increase in the moving average of HbA1 values for 6 months by 1, 2 or 3% was 1.18, 1.39 or 1.63, respectively. When the HbA1 level was adjusted to its average value in the subjects (9.6%), the estimated cumulative retinopathy progression rate for 6, 12, 18 or 24 month follow-up was 3.6, 14.5, 22.5 or 30.5%, respectively. The differences in the cumulative retinopathy progression rate between a well-controlled group with a low moving average of HbA1 value (3% lower than the average) and a poorly-controlled group with a high moving average of HbA1 value (3% higher than the average) were estimated as 3% (6-month follow-up) and 23% (24 months).

Effect of rapid glycemic control on progression of diabetic retinopathy.

The effect of the start of glycemic control on the progression of retinopathy was investigated by a case-control study. The changes in glycosylated hemoglobin (HbA1) were compared between a case group, diabetic cases showing progression of retinopathy (Group 1), and a control group, diabetic cases showing no progression of retinopathy (Groups 2-A and 2-B). Group 2-A was matched with Group 1 on the basis of the grade of retinopathy at the first examination and other clinical data. Group 2-B was matched with Group 1 in terms of HbA1 value and methods of control, but had no retinopathy or background retinopathy. The retrospective follow-up period for the three groups was 24 months. On the basis of the respective matching factors, Groups 1 and 2-A were divided into 9 blocks of homogeneous subjects, and Groups 1 and 2-B were similarly divided into 6 blocks. The resulting data was evaluated block by block, using the analysis of variance (ANOVA) and a conditional logistic regression analysis. In Group 1, the HbA1 value decreased rapidly 10-6 months before the progression of retinopathy, but the HbA1 value did not change in Groups 2-A and 2-B during the 24-month follow-up. The difference in the estimated mean HbA1 value between 10-9 months and 1-0 month before the progression of retinopathy was 2.46% greater in Group 1 than in Group 2-A, as determined by ANOVA. The relative risks of a 1, 2 and 3% increase in HbA1 value for 7-6 months were estimated as 1.6, 2.4 and 3.8, respectively, by conditional logistic regression analysis. These findings indicate that the decrease in HbA1 value during any 6-month period should be limited to less than 2% in order to prevent the progression of retinopathy. It is also evident that too rapid a decrease at the initiation of glycemic control could cause severe or transient exacerbation of the progression of retinopathy.

Stimulation and inhibition of angiogenesis in diabetic retinopathy.

PURPOSE: To investigate the role of stimulators and inhibitors of angiogenesis in the pathogenesis of diabetic retinopathy. METHODS: Undiluted vitreous samples and simultaneous paired plasma samples were obtained from 30 diabetic patients (35 eyes) undergoing vitreous surgery. The levels of vascular endothelial growth factor (VEGF), endostatin, and platelet factor-4 (PF-4) were measured simultaneously in each specimen by enzyme-linked immunosorbent assay. The severity of diabetic retinopathy was evaluated according to the modified Early Treatment Diabetic Retinopathy Study retinopathy severity scale. RESULTS: Vitreous levels of VEGF and endostatin were significantly correlated with the severity of diabetic retinopathy (rho = 0.52, rho = 0.48, respectively), but the vitreous level of PF-4 was not (rho = 0.12). Vitreous levels of VEGF, endostatin, and PF-4 were not significantly correlated with their plasma levels. The vitreous level of VEGF was significantly correlated with that of endostatin (rho = 0.42). The VEGF concentration was significantly higher in the vitreous than in the plasma, while the endostatin concentration was not. CONCLUSIONS: The present study showed that VEGF and endostatin were expressed in the vitreous of patients with diabetic retinopathy and may be involved in the pathogenesis of this condition.

Superficial spreading-type mucosa-associated lymphoid tissue (MALT) lymphoma in the stomach--a case report.

We presented a case of a 71-year-old woman who presented irregular mucosal folds with tiny depressions and multiple erosions with ulceration in the stomach, on endoscopy and roentgenography. Histological findings from biopsy specimens showed dense and mildly atypical lymphoid-like cells invading the submucosa. Immunohistochemical examinations revealed monoclonal reactivity of Heavy-chain. She was then diagnosed to have low grade malignant lymphoma in the stomach and underwent total gastrectomy. The resected cancer demonstrated the pathological features including small lymphocytic plasmacytoid cells and lymphoepithelial lesions characteristic of a mucosa-associated lymphoid tissue (MALT) lymphoma. The lymphoma cells expressed B cell markers with a phenotype of IgG and lambda type. It is difficult to make a firm diagnosis of a MALT lymphoma from only small biopsy specimens. Accordingly it is necessary to complete the observed clinical process, endoscopic and roentgenographic findings with immunohistochemical characteristics to determine diagnosis. The MALT lymphoma should be treated as a low-grade malignancy and diagnosis sufficiently early can lead to a favorable prognosis.

[The present status of ophthalmological management for diabetics].

A questionnaire regarding management of patients with diabetes was mailed to 315 ophthalmologists. The status of ophthalmological management at the hospitals and clinics was investigated. The return rate of questionnaires was 73%. The problems at the clinics were 1. many cases have ophthalmological symptoms at the first ophthalmological examination (longer time from the onset of diabetes to the first ophthalmological examination), 2. appropriate cooperation between ophthalmology and internal medicine is lacking, 3. the collection of information on blood glucose control level is difficult, and 4. there is not enough consultation by appointment. The common problems to both hospitals and clinics were 1. satisfactory measures are not taken regarding dropout ophthalmology patients, and 2. a system of patient education does not exist. There is a pressing need for comprehensive measures to be taken by medical association leaders and medical administrators to settle these problems.

[Relationship between progression of diabetic retinopathy and blood glucose control].

The relationship between the progression of diabetic retinopathy and consecutive blood sugar control measured by HbA1 levels was statistically analyzed based on 422 eyes of 211 diabetic patients who were followed up 2 years or more. Cox regression (proportional hazard model) with HbA1 as a time-dependent covariate was applied and the relative risk of HbA1 vis-à-vis the progression of retinopathy was evaluated. For a given value of HbA1 at each time point during progression, the average for x preceding months was calculated and the value of x was changed from 1 to 30 to assess the cumulative effect of HbA1. The cumulative effect of HbA1 was statistically significant and the absolute value of the coefficient changed little if the periods for calculating the average are equal to or more than 6 months. Relative risks corresponding to the increase of HbA1 (averaged at 6 months) by 1, 2 and 3% were 1.18, 1.39 and 1.63, respectively. When the HbA1 level was adjusted to its average value (9.56%), estimated cumulative progression rates for 6, 12, 18 and 24 follow-up months were 3.6, 14.5, 22.5 and 30.5%, respectively. Difference of cumulative progression rate between a well-controlled group with a low (3% less than the average) HbA1 value and a poorly-controlled group with a high (3% higher than the average) HbA1 value was estimated as 3% (6 follow-up months) and 23% (24 months).

[Effect of the start of glycemic control on the progression of diabetic retinopathy].

The effect of the start of glycemic control on retinopathy progression was investigated. The changes of glycosylated hemoglobin (HbA1) were compared between the retinopathy progression group (Group 1, 24 eyes) and the non-progression group (Group 2, 23 eyes). The follow-up period was 24 months. The grades of retinopathy, age, duration of diabetes mellitus (DM), sex, and manner of DM control in these subjects were matched between the two groups. They were classified into 9 strata according to the matched systemic factors. In Group 1, HbA1 value decreased rapidly 6 or 7 months before the retinopathy progression, but did not change in Group 2 during 24 months. The change rate was significantly different between Group 1 and Group 2. The block efficacy for 6-7 months follow-up was also statistically significant between the two groups by analysis of variance (ANDVA). The estimated mean HbA1 value for the 9-10 month period in Group 1 was 2.46% less than that of Group 2. The higher the HbA1 value, the higher the relative risk (odds ratio) of retinopathy progression. The relative risk of retinopathy progression of the mean HbA1 value was highest for 9-10 month period. The relative risks of 1, 2, and 3% decrease of HbA1 for 9-10 months were 1.7, 2.8, and 4.7, respectively.

[Diabetic retinopathy score and fuzzy logic in therapy].

A system for determining optimal treatment of diabetic retinopathy was devised on the basis of fuzzy logic. In a previous study we devised a new retinopathy scoring system from the multivariate analysis of fluorescein angiography findings. Using this scoring system we expressed severities as language terms and assigned them membership functions which showed grade (0-1). Next, the optimal treatment was determined by defuzzification of the membership functions given to treatment programs corresponding to the severity of retinopathy. This decision system is shown as a nomogram. Users of this system can get the grade for choosing optimal treatment after they input the retinopathy score into the nomogram. Assessment of this fuzzy decision system was performed by changes in the extent of dye leakage (Le) and neovascularization (NV) in 86 eyes of 48 diabetic patients followed up for over 12 months. When the grade of choice was over 0.5, the evaluation of choosing optimal treatment was 74% by Le and 68% by NV. Le improved but NV did not improve when the grade of choice was elevated to a higher level.

[Risk factors for occurrence and progression of diabetic retinopathy].

The risk factors for the occurrence and progression of diabetic retinopathy were estimated in 1084 diabetic subjects (4358 person-years) by logistic regression analysis. The diabetic duration, the average of HbA1C for every year of observation, the range of HbA1C, the difference of HbA1C between the first visit to our clinic and the average of one year of HbA1C were statistically significant covariates for the risk of the occurrence of retinopathy. The relative risks of the occurrence of retinopathy as compared with the diet were estimated as 2.02 in oral administration of medicine and 1.86 in insulin therapy. The interaction between the difference of HbA1C and the average of HbA1C was statistically significant for the progression of retinopathy. When the response surface was estimated, the risk of progression of retinopathy differed greatly according to the blood glucose control level.

[Retinopathy score: assessment of fluorescein angiography findings in diabetic retinopathy].

Scoring of the pathological changes shown by fluorescein angiography in patients with diabetic retinopathy was performed to assess the severity of retinopathy and the effectiveness of treatment. A total of 480 fluorescein angiography sessions were performed in 142 eyes of 71 patients. Eleven items of 7 signs were assessed (microaneurysms, extent of non-perfused area (NP), intraretinal microvascular abnormalities, neovascularization from the optic disc or from retinal vessels, leakage from retinal vessels and macular edema). First, the gradings for the 11 items were analysed by the quantification analysis method III and classified into 6 clusters. These 6 clusters corresponded to the grades of retinopathy. The relative severity of each grade of retinopathy was calculated by this analysis. Second, in order to determine the relative contribution of each item to the grading of retinopathy, the quantification analysis method I was used with the above 6 grades of retinopathy, which were adopted as outside criteria. The regression coefficient of the extent of NP was found to be greatest. Scores were defined as the summation of the category numbers (weights) of the main 7 items.

[Effective mechanisms of laser photocoagulation for neovascularization in diabetic retinopathy].

Effective mechanisms of laser photocoagulation for neovascularization in diabetic retinopathy were investigated in regard to change in oxygen pressure in the retina and vitreous and cytokines related to ischemia. The mechanism of laser photocoagulation is suggested to be as follows. 1. Destruction of the outer retina, especially of photoreceptors that have high oxygen consumption decreases metabolic function of the outer retina and its oxygen consumption. 2. The destruction allows increase of oxygen diffusion from choroidal vessels to inner retina, which improves the metabolic function by equilibrating oxygen demand and supply in the inner retina. (3) Production and secretion of neovascular factors such as vascular endothelial growth factor (VEGF) is decreased by the improvement of hypoxia. 4. The neovascularization is decreased by the synergistic effect between the neovascular factors and suppressors such an VEGF, fibroblast growth factor (FGF), and transforming growth factor-beta (TGF-beta). The improvement of the retinal ischemia and the decrease of cytokines are implicated in the regression of neovascularization by the laser photocoagulation for diabetic retinopathy.

[Reliability of evaluating grade of diabetic retinopathy].

The inter-rater and intra-rater reliability of stage-evaluation for diabetic retinopathy using Fukuda's classification was assessed by the kappa coefficient. The raters consisted of 16 ophthalmologists in 3 institutions. The kappa coefficient was calculated to evaluate the inter-rater reliability. Evaluation was performed twice. The value of the kappa coefficient for the first evaluation was 0.18 and that for the second time evaluation was 0.081. The kappa coefficient for evaluation of the change of retinopathy grade was 0.24. The agreement of evaluation using color fundus photographs was higher than that using both color fundus photographs and fluorescein angiograms. The agreement of the evaluation of retinopathy grades did not correlate with periods of experience as ophthalmologists. The intra-rater agreement of the evaluation of retinopathy grades was 60-70%. These results suggested that the reliability of the evaluation of retinopathy grades was not high among ophthalmologists and that standardization in clinical investigation of diabetic retinopathy was necessary using fundus photographs and fluorescein angiograms.

[The role of cytokines in the pathogenesis of diabetic retinopathy].

PURPOSE: To investigate the role of cytokines and advanced glycation end products(AGEs) in the pathogenesis of diabetic retinopathy, we measured vascular endothelial growth factor(VEGF), interleukin-6(IL-6), tumor necrosis factor-alpha(TNF-alpha), transforming growth factor-beta 1(TGF-beta 1), and pentosidine(an AGE) levels in aqueous, vitreous, and paired plasma obtained from diabetic patients. RESULTS: The aqueous levels of VEGF and IL-6 were positively correlated with the grade of clinical severity of diabetic retinopathy (both VEGF and IL-6, p < 0.001). Other cytokines and pentosidine levels were not significantly associated. The aqueous levels of VEGF and IL-6 were higher than the plasma levels(VEGF p = 0.02, IL-6 p < 0.001). CONCLUSION: Within the intraocular area VEGF and IL-6 are produced and participate in the pathogenesis of hyperpermeability of retinal vessels in preproliferative diabetic retinopathy.