Optical coherence tomography and vessel diameter changes after intravitreal bevacizumab in diabetic macular oedema

Purpose: To assess the effect of intravitreal bevacizumab on diabetic macular oedema (DMO) and retinal vessel calibres. Methods: We performed a consecutive case series study in which 10 consecutive eyes with diffuse DMO, two of which had not previously been treated, received an intravitreal injection of bevacizumab 1 mg, which was followed by two more injections at 6‐week intervals. Fundus photography and optical coherence tomography (OCT) were carried out at baseline immediately before injection and at 1, 2.5 and 4 months after the first injection. Outcome measures were best corrected visual acuity (BCVA) in Early Treatment Diabetic Retinopathy Study letters, macular volume, foveal subfield thickness and vessel diameter measurement. Results: Intravitreal administration of bevacizumab was followed by a mean increase in BCVA of 7.3 ± 17 (mean ± standard deviation) letters between baseline and month 4, which was 1 month after the last injection (p < 0.0001). This was accompanied by a reduction in mean macular volume from 9.90 ± 1.9 mm³ to 8.96 ± 2.4 mm³ (p = 0.002) and in foveal subfield thickness from 447 ± 117 μm to 388 ± 117 μm (p = 0.03). Two eyes with early proliferative diabetic retinopathy lost all signs of proliferation without any evidence of fibrosis. Although there was a trend towards vasoconstriction, the changes in vessel diameters (arteries and veins) after 4 months of intravitreal Avastin injection were not statistically significant (p = 0.9 and p = 0.17, respectively). Foveal thickness in non‐injected fellow eyes with DMO changed from 428 ± 153 μm at baseline to 383 ± 151 μm at 4 months (p = 0.1), which did not reach statistical significance. Conclusions: Intravitreal bevacizumab 1 mg every 6 weeks was followed by a moderate reduction in DMO without normalization of foveal and macular thickness. Our observations suggest that a larger study where patients are examined sooner after injection is needed to elucidate the potential relationship between changes in retinal vessel diameters and thickness changes in DMO.     

Both lipid and protein intakes stimulate increased generation of reactive oxygen species by polymorphonuclear leukocytes and mononuclear cells

BACKGROUND: It was recently shown that glucose challenge leads to increased generation of reactive oxygen species (ROS) by polymorphonuclear leukocytes (PMNs) and mononuclear cells (MNCs). OBJECTIVE: To further elucidate the relation between nutrition and ROS generation, we investigated the effect of lipid and protein challenges on ROS generation by leukocytes. DESIGN: After having fasted overnight, one group of healthy subjects consumed a carbohydrate- and protein-free cream preparation (1257 kJ) and another group of healthy subjects consumed an equienergetic pure preparation of casein. Sequential blood samples were obtained after the intake of cream and casein. ROS were measured by chemiluminescence after stimulation by N-formyl-methionyl-leucinyl-phenylalanine. Lipid peroxidation was measured as thiobarbituric acid-reactive substances (TBARS) and alpha-tocopherol was measured by HPLC. RESULTS: ROS generation by MNCs and PMNs increased significantly 1, 2, and 3 h after cream intake and 1 h after protein intake. Cholesterol concentrations did not change significantly, whereas triacylglycerol concentrations increased significantly 2 h after cream intake. Total TBARS concentrations increased 1 h after cream intake and remained elevated 3 h after intake, but the increase was not significant when corrected for changes in triacylglycerol. After casein intake, total cholesterol, triacylglycerol, and TBARS concentrations did not change significantly. alpha-Tocopherol concentrations did not change significantly after either cream or casein intake. CONCLUSIONS: Both fat and protein intakes stimulate ROS generation. The increase in ROS generation lasted 3 h after cream intake and 1 h after protein intake. Cream intake also caused a significant and prolonged increase in lipid peroxidation. These data are important because increased ROS generation and lipid peroxidation are key events in atherogenesis.     

Restoring mismatch repair does not stop the formation of reciprocal translocations in the colon cancer cell line HCA7 but further destabilizes chromosome number

An important anticarcinogenic function of the mismatch repair (MMR) system is its role in preventing recombination between similar, but nonidentical (homeologous) sequences, thus preventing chromosomal rearrangements. We recently identified a novel chromosomal instability (CIN) phenotype in an MMR defective colon cancer cell line (HCA7) characterized by an ongoing tendency to multiple reciprocal chromosomal translocations. To analyse the relation between MMR and chromosomal changes more closely, the HCA7 stem clone was divided into three stocks. The first was stably transfected with MLH1 expression plasmid, the second was regularly exposed to the demethylating agent 5-azacytidin to re-express the hypermethylated MLH1 gene, and the third was an unmanipulated control stock. All stocks were propagated in vitro for 55-80 passages and, furthermore, some of the early passages were irradiated to induce DNA double-strand breaks. Multiplex-fluorescent in situ hybridization (M-FISH) analysis showed that all three stocks acquired varying numbers of reciprocal translocations and other structural changes at some point. Interestingly, the control stock, which is MMR defective, maintained its numerical chromosomal stability, while some of the MMR-proficient clones showed additional numerical instability. Although the control stock was less sensitive to irradiation, its surviving clones showed marked stability of chromosome structure and number compared to the MMR-competent stocks. These results show that restoring MMR does not prevent the development of reciprocal translocations but rather predisposes cells to numerical CIN after irradiation. Thus, the accumulating data suggest that MMR defect may not be necessary for the development of reciprocal chromosomal translocations but might be permissive.     

Comprehensive characterization of HNPCC-related colorectal cancers reveals striking molecular features in families with no germline mismatch repair gene mutations

A considerable fraction of families with HNPCC shows no germline mismatch repair (MMR) gene mutations. We previously detected 'hidden' MMR gene defects in 42% of such families, leaving the remaining 58% 'truly' mutation negative. Here, we characterized 50 colorectal carcinomas and five adenomas arising in HNPCC families; 24 truly MMR gene mutation negative and 31 MMR gene mutation positive. Among 31 tumors from MMR gene mutation positive families, 25 (81%) had active Wnt signaling as indicated by aberrant beta-catenin localization with or without CTNNB1 mutations, compared to only 7/18 tumors from MMR gene mutation negative families (39%; P=0.005). CGH studies revealed stable profiles in 9/16 (56%) of MMR gene mutation negative tumors, which was significantly associated with membranous beta-catenin (P=0.005). Tumors with membranous beta-catenin from the MMR gene mutation negative group also showed low frequency of TP53 mutations compared to those with nuclear beta-catenin. Thus, a majority of the MMR gene mutation negative cases exhibited a novel molecular pattern characterized by the paucity of changes in common pathways to colorectal carcinogenesis. This feature distinguishes the MMR gene mutation negative families from both HNPCC families linked to MMR defects and sporadic cases, suggesting the involvement of novel predisposition genes and pathways in such families.     

The impact of CAG repeats in exon 1 of the androgen receptor on disease progression after prostatectomy

BACKGROUND: The authors examined the impact of the number of CAG repeats in exon 1 of the androgen receptor on disease progression among men with prostate carcinoma after prostatectomy. This polymorphism has been associated with alterations in activity of the androgen receptor in in vitro systems and with the risk of clinically diagnosed prostate carcinoma in some epidemiologic studies. An earlier series found that, among men at low risk of progressive disease, a small number of CAG repeats predicted a high risk of recurrence, and the impact of CAG repeats varied among men with different risks of progressive disease. METHODS: The authors analyzed specimens from a large clinical series of fixed tissue specimens from men who underwent prostatectomy at a single institution, including 413 American white men (WM) and 298 African-American men (AAM), with 5-10 years of available clinical follow-up. RESULTS: There was little association between the number of CAG repeats and extent of disease, Gleason score, and preoperative PSA level at diagnosis. Overall, patients who had > 18 CAG repeats had a greater risk of recurrence compared with patients who had 18 CAG repeats had an estimated 52% increased risk of disease recurrence. The increased risk could be attributed to men who were at high risk of recurrence.     

Transjugular intrahepatic portosystemic shunt in a living donor left lateral segment liver transplant recipient: technical considerations

The technical aspects of placing transjugular intrahepatic portosystemic shunts (TIPS) in liver transplant recipients with full allografts have well been described. In the era of live related hepatic donors, and the growing population of their recipients, it is likely that TIPS shunts will be placed in failing transplant lobes/segments. Growing allografts that are initially undersized can have an unconventional orientation of the hepatic and portal veins, which may also change with remodeling and rotation of the graft during their growth. The authors review the technical differences for TIPS procedures in transplants, particularly split grafts. They describe a technically successful TIPS procedure in an undersized and remodeled left lateral segment liver recipient and the additional difficulty this may pose.