Emission of low-energy positronium from alkali-metal coated single-crystal tungsten surfaces

We have measured the time-of-flight of ortho-positronium emitted from Cs-, Na- and Li-coated single-crystal tungsten surfaces. The data obtained after the coating show a new positronium energy component with a specific energy loss in addition to the component whose emission energy is simply determined by the positron and the electron work functions. We suggest that this new component is attributed to the formation of positronium accompanied by inter-band transition and/or surface plasmon excitation at the surfaces.

Structure determination of the rutile-TiO2(110)-(1 × 2) surface using total-reflection high-energy positron diffraction (TRHEPD)

Detailed structure of the rutile-TiO₂(110)-(1 × 2) has been determined using the newly developed technique of total-reflection high-energy positron diffraction (TRHEPD).

Characterization of ion-irradiated poly-L-lactic acid using nano-cutting

Effects on the mechanical strength of poly-L-lactic acid (PLLA) upon irradiation with 150 keV He(+) ion were studied. Changes in the irradiated surface were investigated using a surface texture and contour measuring instrument and an atomic force microscope. Observations made with the atomic force microscope revealed that the irradiated surface subsided significantly as the fluence increased. In order to investigate the dependence on fluence of the depth of the Bragg peak for the ion implantation, the cutting strength, Σ, was analysed [F. Saito, I. Nishiyama and T. Hyodo, Mater. Lett., 2012, 66, 144-146]; this value is an indicator of the strength of a material against cutting, and is obtained from the cutting resistance. The averaged ion projected range increased from about 1.1 μm for a fluence of 1 × 10(15) He(+)/cm(2) to about 4 μm for a fluence of 1 × 10(16) He(+)/cm(2). The density of the region following irradiation was estimated using a combination of cutting resistance measurements and positron annihilation γ ray Doppler broadening measurements made with an energy-variable positron beam. The density decreased from the value of 1.27 g cm(-3) to about 0.6 g cm(-3) after irradiation with a fluence of 3 × 10(15) He(+)/cm(2). By considering the decrease in the density and the subsidence of the surface, it is concluded that only 30% of the original weight remained in the irradiated region after exposure to the He(+) ions. Anisotropic change in the cutting resistance suggests that mechanical strength in the direction normal to the surface increased while that in the lateral direction decreased.

Clinical application of 3D arterial spin-labeled brain perfusion imaging for Alzheimer disease: comparison with brain perfusion SPECT

BACKGROUND AND PURPOSE

Alzheimer disease is the most common neurodegenerative disorder with dementia, and a practical and economic biomarker for diagnosis of Alzheimer disease is needed. Three-dimensional arterial spin-labeling, with its high signal-to-noise ratio, enables measurement of cerebral blood flow precisely without any extrinsic tracers. We evaluated the performance of 3D arterial spin-labeling compared with SPECT, and demonstrated the 3D arterial spin-labeled imaging characteristics in the diagnosis of Alzheimer disease.

MATERIALS AND METHODS

This study included 68 patients with clinically suspected Alzheimer disease who underwent both 3D arterial spin-labeling and SPECT imaging. Two readers independently assessed both images. Kendall W coefficients of concordance (K) were computed, and receiver operating characteristic analyses were performed for each reader. The differences between the images in regional perfusion distribution were evaluated by means of statistical parametric mapping, and the incidence of hypoperfusion of the cerebral watershed area, referred to as "borderzone sign" in the 3D arterial spin-labeled images, was determined.

RESULTS

Readers showed K = 0.82/0.73 for SPECT/3D arterial spin-labeled imaging, and the respective areas under the receiver operating characteristic curve were 0.82/0.69 for reader 1 and 0.80/0.69 for reader 2. Statistical parametric mapping showed that the perisylvian and medial parieto-occipital perfusion in the arterial spin-labeled images was significantly higher than that in the SPECT images. Borderzone sign was observed on 3D arterial spin-labeling in 70% of patients misdiagnosed with Alzheimer disease.

CONCLUSIONS

The diagnostic performance of 3D arterial spin-labeling and SPECT for Alzheimer disease was almost equivalent. Three-dimensional arterial spin-labeled imaging was more influenced by hemodynamic factors than was SPECT imaging.

CT and MR cholangiography: advantages and pitfalls in perioperative evaluation of biliary tree

Recent developments in imaging technology have enabled CT and MR cholangiopancreatography (MRCP) to provide minimally invasive alternatives to endoscopic retrograde cholangiopancreatography for the pre- and post-operative assessment of biliary disease. This article describes anatomical variants of the biliary tree with surgical significance, followed by comparison of CT and MR cholangiographies. Drip infusion cholangiography with CT (DIC-CT) enables high-resolution three-dimensional anatomical representation of very small bile ducts (e.g. aberrant branches, the caudate branch and the cystic duct), which are potential causes of surgical complications. The disadvantages of DIC-CT include the possibility of adverse reactions to biliary contrast media and insufficient depiction of bile ducts caused by liver dysfunction or obstructive jaundice. Conventional MRCP is a standard, non-invasive method for evaluating the biliary tree. MRCP provides useful information, especially regarding the extrahepatic bile ducts and dilated intrahepatic bile ducts. Gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced MRCP may facilitate the evaluation of biliary structure and excretory function. Understanding the characteristics of each type of cholangiography is important to ensure sufficient perioperative evaluation of the biliary system.

Early-stage malignant peripheral nerve sheath tumour arising from a solitary neurofibroma

We report a case of early-stage malignant peripheral nerve sheath tumour (MPNST) found in a solitary neurofibroma, and its CT and MRI findings. A 19-year-old male with no known history of a neurofibromatosis presented with a painless swelling in the left forearm. CT and MRI scans showed a well-circumscribed, intermuscular mass, which was 6.0 cm in diameter and contained a strongly enhanced 1.0 cm nodular structure with surrounding oedema. Peripheral nerve continuity with the mass was not seen. Histological evaluation proved the nodular structure was an MPNST component completely surrounded by neurofibroma. Following an excisional biopsy with wide margins, the patient was followed up for a year without treatment and no recurrence was observed.

Photodetachment of positronium negative ions

Photodetachment of the positronium negative ion, a bound state of one positron and two electrons, has been observed. Development of a method to produce the ions efficiently using a Na coated tungsten surface has enabled the first observation of the photodetachment. The obtained lower limit of the photodetachment cross section for the wavelength of 1064 nm is consistent with the theoretical calculations reported so far. The experimental field developed in the present work gives new opportunities to explore the quantum mechanical three-body problem and to develop energy-tunable positronium beams.

Evaluation of functional relationships for predicting mainstream smoke constituent machine yields for conventional cigarettes from the Japanese market

The objective of this study was to predict mainstream smoke constituent yields for conventional filter cigarette brands on sale in Japan between 2004 and 2005. Mainstream smoke was generated under ISO machine smoking conditions. Developed functional relationships indicate the validity of benchmarking even for a market which is characterized by a diversity of tobacco blend types. Smoke yields were in general well predicted by linear regression with "tar" (R2>or=0.7). Blend-type-sensitive analytes like tobacco-specific nitrosamines showed improved prediction relationships after blend stratification or regressing against nitric oxide (NO, R(2)>0.7). Relationships calculated from 83 exploratory brands were validated with a subset of 23 validation brands. Seventy-five to one-hundred percent of the validation brand yields were inside the 95% prediction intervals. The mean-relative prediction error over all analytes was 24% after stratification. Smoke constituents yields analyzed in 2002 from 96 Japanese market products were well predicted and indicate the model validity over time. Similar relationships were observed when comparing American blended filter cigarette yields from Japan and worldwide markets. Consistent with reported results from previous benchmark studies and market surveys mainstream smoke constituent yields are well predictable when "tar" (and NO) yields are known.

Minimal change nephrotic syndrome, lymphadenopathy and hyperimmunoglobulinemia after immunization with a pneumococcal vaccine

A 67-year-old female was admitted to our hospital with eruption and cervical lymphadenopathy which occurred one week after pneumococcal vaccination. Polyclonal hyperimmunoglobulinemia (IgG 6,620 mg/dl) and mild plasma cell proliferation (6.4%) in a bone marrow specimen were found, but a lymph node aspiration biopsy showed no specific findings. Normochromic and normocytic anemia with a positive direct Coombs test were also confirmed. Short-term intensive steroid therapy was given, but the systemic eruption and lymphadenopathy continued. About 4 months after vaccination, she suffered from edema in her face and legs and visual disturbance. When massive proteinuria (10.4 g/day) was found, she was admitted to our ward. A renal biopsy specimen showed a minor glomerular abnormality with mild interstitial plasmacytic infiltration. An abdominal CT scan showed hepatosplenomegaly and para-aortic lymphadenopathy. Uveitis was also found by ophthalmoscopy. These abnormalities completely disappeared after intensive steroid therapy including pulse therapy. On the basis of her clinical course and laboratory findings, it was suggested that minimal change nephrotic syndrome might be induced after vaccination, possibly due to hypersensitivity syndrome.

Antitumor effect of bcl-2 antisense phosphorothioate oligodeoxynucleotides on human renal-cell carcinoma cells in vitro and in mice

BACKGROUND AND PURPOSE

Programmed cell death is a genetically regulated pathway that is altered in many cancers. This process is, in part, regulated by the bcl-2 oncogene. Antisense oligodeoxynucleotides (ODNs) targeted to specific oncogenes have been used with some therapeutic success in animal models of leukemia and melanoma cells and human Hodgkin's lymphoma. We evaluated the effects of antisense ODNs targeted to the bcl-2 oncogene on the proliferation of human renal-cell carcinoma (RCC) cells in vitro and on the growth of human RCC xenografts in BALBc nude (nu/nu) mice.

MATERIALS AND METHODS

Expression bcl-2 mRNA in five RCC cell lines (ACHN, Caki-1, RCZ, RCW, and OS-RC-2) was analyzed by reverse transcriptase-polymerase chain reaction. The effects of phosphorothioated ODNs containing human bcl-2 sense and bcl-2 antisense sequences that were transfected with Lipofectin on the proliferation and viability of cultures of established human RCC cell lines were determined by MTS assay. The expression of Bcl-2 protein in ACHN tumor cells following antisense bcl-2 (AS2) ODN treatment was evaluated by Western blot analysis, and the extent of apoptosis in these cells was determined by fluorescence-activated cell sorter (FACS) analysis. The antitumor activity in ACHN xenografts in nu/nu mice was monitored by measuring differences in tumor weight in treated and control mice.

RESULTS

Expression of bcl-2 mRNA was detected in all five RCC lines. Treatment with antisense bcl-2 ODNs inhibited the growth of all tested RCC cells and decreased Bcl-2 protein expression in ACHN cells. The AS2 antisense ODN complementary to the coding region of bcl-2 mRNA showed a superior antiproliferative effect compared with AS1 ODN complementary to the translation initiation region. Inhibition by antisense bcl-2 ODNs of ACHN cells was dose dependent. The FACS analysis revealed that growth inhibition was associated with the induction of programmed cell death. In vivo, AS2 ODN antitumor activity was noted in locally injected groups.

CONCLUSIONS

Treatment of human RCC with antisense ODNs targeted to bcl-2 inhibits growth and is associated with the induction of programmed cell death. These results suggest therapeutic use of antisense bcl2 in the treatment of RCC.

Recovery of 18F from [18O] water by electrochemical method

An electrochemical method for producing 18F sources for the slow positron beam was applied to the recovery of 18F from H2(18)O water. The 18F of activities 150-227 mCi (5.55-8.40 GBq) was electro-deposited on a graphite rod and then emitted into pure water. The best result of the efficiency for the electro-deposition for 5 min was 97% and that for the electro-emission for 5 min was 89%. The H2(18)O water is expected to be reused much more easily by this method than by the ion exchange resin method. The metal impurities contained in the 18F solution were considerably reduced by using this method.

Contrast-enhanced intraductal ultrasonography for thickened bile duct wall

PURPOSE

We carried out this study to evaluate the usefulness of contrast-enhanced intraductal ultrasonography (ceIDUS) in the differentiation of thickened bile duct wall at the hepatic bifurcation caused by malignant tumor from that caused by cholangitis.

METHODS

Seven patients (two with primary sclerosing cholangitis [PSC], one with secondary sclerosing cholangitis [SSC], and four with bile duct carcinomas [BDC] at the hepatic bifurcation underwent endoscopic ceIDUS, in which we used Levovist. The recorded images of echo-brightness were analyzed histographically.

RESULTS

The bile duct wall, in PSC and SSC, but not in BDC, was enhanced by Levovist.

CONCLUSION

ceIDUS with histographic analysis may be useful for distinguishing thickened bile duct wall caused by malignant tumor from that caused by cholangitis.

Duodenal stenosis after endoscopic biliary metallic stent placement for malignant biliary stenosis

BACKGROUND

Some patients who undergo endoscopic insertion of biliary metallic stents for malignant biliary stenosis later develop symptomatic duodenal stenosis due to tumor invasion.

METHODS

We compared the development of symptomatic duodenal stenosis in patients who had undergone endoscopic biliary metallic stent insertion (metallic stent group) with that in patients who had undergone either endoscopic biliary drainage or percutaneous transhepatic biliary drainage with a plastic stent (nonmetallic stent group). Fourteen patients in the metallic stent group were matched with 14 patients in a nonmetallic stent group. All patients had a Karnofsky performance status score of greater than 90% and were clinical stage IV when they underwent biliary decompression.

RESULTS

Although there was no difference in survival time between the 2 groups, 5 of 14 patients in the metallic stent group developed symptomatic duodenal stenosis due to tumor invasion during the observation period whereas this occurred in only 1 of 14 patients in the nonmetallic stent group. Multiple logistic regression analysis indicates that the type of stent (p = 0.022) and survival time (p = 0.002) are 2 independent prognostic factors for the development of symptomatic duodenal stenosis.

CONCLUSIONS

Patients treated with endoscopic biliary metallic stent insertion are prone to develop symptomatic duodenal stenosis due to tumor invasion compared with those treated with either endoscopic retrograde biliary drainage or percutaneous transhepatic biliary drainage with a plastic stent.

In vitro and in vivo generation and kinetics of glycosylation products in peritoneal dialysis effluents

There are indications that advanced glycosylation end-products (AGEs) may affect in some manner the functions of the peritoneum. Only a few reports discuss the actual generation of glycosylated proteins and the intraperitoneal kinetics involved during continuous ambulatory peritoneal dialysis (CAPD). To demonstrate the formation of AGEs and their time-courses in peritoneal dialysis (PD) effluents, measurements were made of furosine, carboxymethyl lysine (CML), and pentosidine as glycosylation markers in vitro and in vivo using PD effluents obtained every 2 hours for up to 8 hours from 3 nondiabetic CAPD patients. Furosine and CML were found to be generated relatively early (within 6 hours), and their de novo formation was markedly enhanced subsequent to glucose addition. Furosine and CML production increased in proportion to glucose concentration. Pentosidine production did not change with time for up to 24 hours, and was not induced by glucose during this period. Carboxymethyl lysine production appeared to be suppressed in vitro with the addition of serum protein. Furosine in the intraperitoneal dialysate was initially the same as that in the plasma, but increased to twice as much in just 2 hours in vivo. Production of CML increased, but apparently was suppressed with leakage of plasma protein into the dialysate; this possibly may have been due to dilutional or antiglycation effects in the plasma. No stimulation of pentosidine production could be detected in the intraperitoneal dialysate even at 8 hours. The initiation of glycosylation of peritoneal proteins, with generation of furosine and CML but not pentosidine, is clearly shown by the present results to occur relatively early in the intraperitoneal dialysate, i.e., within a matter of hours.

A new endoscopic metallic stenting method for duodenal stenosis: a preliminary report

Palliative duodenal stenting was attempted in three patients with severe duodenal stenosis due to tumor invasion. Two methods were applied for duodenal stenting: the conventional method, which inserts the Ultraflex (stent for esophageal stenosis) along the guidewire under fluoroscopy, and a new method that uses a snare and an endoscope to guide the esophageal stent. The conventional method is often unsuccessful, because the delivery tube is too short, but the latter method appears to be a safe and effective duodenal stenting technique.

Differential diagnosis between glomerular and nonglomerular hematuria by automated urinary flow cytometer. Kitasato University Kidney Center criteria

Objective, fast and easy methods have not been established in the examination of urine sediment to differentiate between glomerular and nonglomerular hematuria. In this study, we used a newly developed automated urinary flow cytometer that can clearly recognize red blood cells (RBC), white blood cells, epithelial cells, bacteria and crystals by their size and fluorescence intensity without sedimentation. 98 urine samples from 31 glomerular and 67 nonglomerular lesions were analyzed by the device, and the criteria to determine the origin of hematuria were established based on the results. Additional 108 cases were tested to evaluate the validity of these criteria. According to the analysis of histograms of urinary RBC size distribution, cases in whom >/=80% of all RBC have forward scatter (FSC) intensities </=126 and <80% of all RBC have FSC intensities >/=84 were regarded as representing the glomerular type. Cases in whom >/=80% of all RBC have intensities FCS >/=84 and <80% all RBC have FSC intensities </=126 were regarded as representing the nonglomerular type. Cases in whom <80% of all RBC have FSC intensities </=126 and <80% of all RBC have FCS intensities >/=84 were regarded as the mixed type. Cases in whom >/=80% of all RBC have FSC intensities </=126 and >/=80% of all RBC have FSC intensities >/=84 were regarded as the nonglomerular type. The sensitivity for glomerular RBC in the first 98 cases was 90.3% and the specificity 92.5%, and in the second 108 cases the values were 100 and 86.6%, respectively. The automated urinary flow cytometer is useful as a means for routine differential diagnosis of hematuria, and at least it is promising as the screening test for differentiation between glomerular and nonglomerular hematuria, because it can examine numerous samples within a short time and does not necessitate any special skill or knowledge.

Intraductal ultrasonography in six patients with endoscopic biliary stenting

The development of endoscopic biliary stenting (EBS), using the Wallstent, to treat patients with obstructive jaundice secondary to unresectable tumors of the pancreas or biliary ducts has led to improved quality of life in these patients. We followed six patients with intraductal ultrasonography (IDUS) after insertion of a Wallstent. In two patients, endoscopic ultrasonography (EUS) was also performed, and in three patients IDUS was repeated every few months. IDUS allowed ingrowth of the tumor or formation of debris in the stent to be observed clearly and easily. Therefore IDUS was considered to be a powerful tool to follow patients after stenting and to decide on the next treatment when reobstruction occurred.

[Plasma cell leukemia (IgA-lambda type) with polyclonal hypergammaglobulinemia]

An 84-year-old woman was admitted to Ehime University hospital because of fever and generalized swelling of lymph nodes. On admission, she did not have any bone diseases. The laboratory data included a WBC count of 60,900/microliter, with 80.5% atypical plasma cells in the peripheral blood and 26.4% in the bone marrow. The patient's serum total protein was 9.3 g/dl with increased polyclonal gamma-globulin (62.4%). Serum levels of LDH (1,986 IU/l) and IL-6 (34.3 pg/dl) were also elevated. Immunofixation-electrophoresis detected a monoclonal band defined as IgA-lambda type, with a broad band of polyclonal immunoglobulin. Southern blotting analysis demonstrated rearranged monoclonal bands in the JH and J lambda genes. Based on these findings, plasma cell leukemia (IgA-lambda type) was diagnosed. The patient was treated with combination chemotherapy for acute lymphocytic leukemia and achieved complete remission. However, she died of aspergillus sepsis two months after admission. After chemotherapy, the patients IgG and IgM levels normalized but IgA still showed a slight increase. IL-6 also decreased, from 34.3 pg/dl to 10.2 pg/dl. To our knowledge, this report is the first in the literature concerning a case of plasma cell leukemia with polyclonal hypergammaglobulinemia.

Percutaneous autotransplantation of parathyroid tissue into the forearm muscles

We developed a simple and easy nonsurgical percutaneous method for autografting parathyroid tissue into the forearm muscles. This method was applied to 30 patients suffering from secondary hyperparathyroidism who were then refractory to medical treatment. The operative results were then compared with 16 patients who underwent treatment using Wells' method. The graft "take," judged by a significant intact parathyroid hormone (PTH) ratio (> 1.5) between grafted and nongrafted arm vein blood, was 82% for the percutaneous method group and 75% for the Wells' method group, respectively. The percentage of recurrent hyperparathyroidism necessitating a subtotal removal of the autograft was equal in the two groups. No complications were noted for either method. Wells' method can thus be replaced by this simple and easy nonoperative method.

Saccharides as osmotic agents in peritoneal dialysate: determination of molecular weight essential for more efficient fluid removal

Glucose has widely been used as an osmotic agent in continuous ambulatory peritoneal dialysis (CAPD) but owing to its low molecular weight (MW), ultrafiltration (UF) in a 6-hour dialysate exchange does not appear sufficient. Thus, in the present study, a search was made to find saccharides that would ensure optimal UF, exceeding that obtained with glucose in a 6-hour dwell period. Rats were intraperitoneally infused with peritoneal dialysate (20 mL/body) containing the same molar concentrations (75.5 mM, 126 mM, or 204 mM) of various osmotic agents including glucose (monosaccharide, MW = 180.16) at concentrations of 1.36%, 2.27%, and 3.86%; maltose (disaccharide, MW = 342.30) at concentrations of 2.58% and 4.32%; maltotriose (trisaccharide, MW = 504.44), at concentrations of 3.81% and 6.36%; and maltopentaose (pentasaccharide, MW = 828.72) at concentrations of 6.26% and 10.4%. Intraperitoneal-fluid volume was measured at 1, 2, 3, 4, and 6 hours. With glucose as the osmotic agent, maximal UF was noted at 2 to 4 hours. UF was more efficient at 6 hours with maltotriose or maltopentaose as the osmotic agent. Even with a trisaccharide or pentasaccharide (molecular weights of 500 to 830), UF at 6 hours was found more efficient, as evidenced by the delay in peritoneal absorption. Fluid removal in 6 hours should be greater when using a dialysate containing oligosaccharides such as maltotriose or maltopentaose in place of glucose.

Effects of osmotic agents on hyaluronan synthesis in human peritoneal mesothelial cells and fibroblasts

Hyaluronan (HA) plays an important role in peritoneal tissue remodeling and the inflammatory process. In this study, attention was directed to the effects of various osmotic agents on HA synthesis in human peritoneal mesothelial cells (HMCs) and fibroblasts (HFBs). Following incubation with growth arrest media for 48 hours, the cells (4 x 10(4)/mL) were incubated for 72 hours in media at various concentrations (50, 100 mmol/L for crystalloid agents and 3.5%, 7% for oncotic agents) of glucose, mannitol, glycerol, sucrose, raffinose, NaCl, combined amino acids, maltodextrin, dextran 70, and hydroxyethylstarch 20. HA synthesis for 72 hours was measured by sandwich-binding protein assay. HMCs synthesized approximately 0.15 ng/cell/72 hours and HFBs 0.09 ng. All crystalloid osmotic agents significantly suppressed HA synthesis by HMCs and HFBs in a concentration-dependent manner. There was no such suppression by any oncotic osmotic agent, which, to the contrary, enhanced the synthesis by 6%-63% in HMCs. In conclusion, HMCs and HFBs may be considered sources of HA in the peritoneal dialysis effluent. Crystalloid osmotic agents suppressed HA synthesis in these cells. Oncotic osmotic agents seem to be less toxic in this regard.

U-50,488H, a selective kappa opioid receptor agonist, ameliorates memory impairments induced by muscarinic autoreceptor agonist, carbachol in mice

We investigated whether carbachol, a muscarinic receptor agonist, induces learning and memory impairments, and U-50,488H, a selective kappa opioid receptor agonist, ameliorates the impairments of learning and memory using a step-down type passive avoidance task in mice. Carbachol induced a dose-related dual response. Carbachol (3 nmol/mouse, i.c.v.) significantly shortened the step-down latency, while lower (1 nmol) and higher (10 nmol) doses of carbachol did not induce learning and memory impairments. U-50,488H (0.64 micromol/kg, s.c.) significantly improved carbachol-induced impairments of learning and memory. These findings suggest that kappa opioid receptor agonists ameliorate learning and memory impairments which may associate with dysfunction of presynaptic cholinergic neurons.

Epiretinal membrane formation in Terson syndrome

Clinical features of epiretinal membranes were examined in 22 eyes of 13 patients with Terson syndrome who were treated with pars plana vitrectomy. The shape and localization of the epiretinal membranes were intraoperatively evaluated and correlated with the presence or absence of posterior vitreous detachment (PVD). Patients with complete PVD, but with no membrane found during surgery, were followed postoperatively. Membrane formation ultimately developed in 13 of the 22 eyes. In eight eyes, PVD was incomplete and the epiretinal membrane was found at the optic disc or along the temporal vascular arcades, displaying retinal folds and vascular tortuosity. Three eyes had massive tractional retinal detachment; five of those with complete PVD developed a thin epiretinal membrane around the posterior pole that became more apparent during long-term follow-up. From these observations, we can classify epiretinal membrane formation in Terson syndrome into two groups: with complete, or with incomplete, PVD. It also appears that multiple pathological processes involving the vitreoretinal interface were responsible for the formation of epiretinal membranes.